


Tropic of Mercury

by seidrade



Category: Marvel Cinematic Universe, Thor (Movies)
Genre: Anal Sex, Body-Sharing is the New Bed-Sharing, Bottom Thor (Marvel), Brotherly Banter, Canon-Typical Violence, Come Eating, Consentacles, Humor and Romance and Smut and Feels, Inspired by Venom (Movie 2018), Light Angst, Light Bondage, M/M, Magical Accidents, Mutual Pining, Porn with Feelings, Possessive Loki (Marvel), Pre-Canon, Sharing a Body, Sibling Incest, Symbiote Loki, Symbiotic Brotherfuckers, Symbiotic Relationship, Telepathic Sex
Language: English
Status: Completed
Published: 2018-11-16
Updated: 2018-11-26
Packaged: 2019-08-24 14:47:26
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 23,835
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16642259
Author URL: https://archiveofourown.org/users/seidrade/pseuds/seidrade
Summary: Thor freezes once more, assessing his next move, but then— a strange sensation washes over his whole body and he suddenly feels faint. Drops heavy to his knees, sweating hot and cold as his insides seem to rearrange themselves, andoh, what in Bor’s blood is going on—Hush, Thor, it’s alright. It’s just me.It’s only then that Thor realizes he’s been making a strained, high-pitched noise in the back of his throat.“Loki?”





	1. Chapter 1

**Author's Note:**

  * For [illwynd](https://archiveofourown.org/users/illwynd/gifts), [ravenbringslight](https://archiveofourown.org/users/ravenbringslight/gifts).



> Loki becoming a symbiote was an idea I’d entertained after seeing Venom. I was moved to actually write it after reading [Illwynd’s](https://archiveofourown.org/users/illwynd/pseuds/illwynd) most excellent short story, [Symbiosis](https://archiveofourown.org/works/16471700).
> 
> The premise is also in homage to [ravenbringslight](https://archiveofourown.org/users/ravenbringslight) and her fantastic use of some of my favorite tropes in her phenomenal Thorki Big Bang fic, [Creeping Ivy](https://archiveofourown.org/works/16409024/chapters/38412968).
> 
> Raven was also my wonderful beta and the first draft of this story was immeasurably improved by her input. (And she saw Venom with me, so I feel she should shoulder some of the blame.) All further errors are my own. 
> 
> I’m also very proud that I get to use the tag ‘consentacles’ in my first ever AO3 post. We’ve come a long way, baby.

Thor was well-used to finding his brother elbow-deep in all sorts of arcane experiments. 

Though Loki would inevitably scold him for letting in a draft, or else harp on about the rarity and delicacy of this obscure ingredient or that one, he usually assented to Thor remaining to observe so long as his attention wasn’t too sorely diverted. (Granted, this usually only lasted for a few minutes until Thor, unthinking, dared to lean against something or ask Loki a question or, Norns forbid, sneeze.)

But it had never resulted in anything like this.

A dissolution potion, Loki had called it— one that could only be contained in an enchanted vial of the purest and rarest Nidavellian silver, mined from perilous ice caverns set deep within the roots of Yggdrasil itself. The heinous, chartreuse brew was theoretically strong enough to melt uru. (Thor had laughed nervously at that, not sure whether to believe him.) 

Why his brother needed such a powerful potion was beyond Thor’s ken, but he’d mentioned aloud that he trusted, at least, that Loki wouldn’t be testing it on Mjolnir. Not if he knew what was good for him.

Loki had turned then, shot him a grin laced with obvious mischief, and Thor had perhaps foolishly relaxed a little— it was the less-than-obvious mischief you had to really watch out for. 

He’d naturally chosen that precise moment to lean against the edge of Loki’s work table, feeling himself a safe distance away from where Loki was completing the final step to activate the potion. But the heavy stone slab was no match for him, nearly upending as soon as Thor put his weight on it. And though he’d instantly known he had done something Very Wrong and pulled back, it was too late. The many priceless and volatile contents of the table had already been launched airborne.

Thor is now watching time stretch out viciously before him. 

Loki’s eyes go wide in horrified panic as he instinctively throws out his hands and tries to settle the table with his seidr, nearly causing the smooth silver vial to slip from his fingers. He desperately grabs for it, clutches it toward him even as vile, glowing chartreuse spills all over his hands and chest— and oh Norns he’s screaming, a high terrible wail, as the enchantment on the potion rapidly envelops him in a terrible sickly glow. Even as Thor rushes forward, there’s a loud explosion and a crack of lightning not his own and he’s thrown hard across the study, his back slamming into an oak bookcase.

Thor’s up and on his feet only seconds later, heart hammering, ears ringing, a roar ripping itself from his throat, but it’s too late. Something has gone horribly, _horribly_ wrong. The study is in complete shambles, broken glass and spilled ingredients and bits of charred, smoking books littered everywhere. There is a network of blackened cracks in the marble table and several chunks of it are missing. And where his brother stood, there is... nothing.

Then he sees it. 

No, not nothing.

Thor is aghast. All that remains is an angry splash of quicksilver liquid across the marble and wisps of acrid blue smoke. He stares for a moment and then realizes something with strange, lucid clarity. The liquid that remains isn’t dissolving the table. Nor is it any longer that terrible, eerie color. It was meant to dissolve… and it has evidently fulfilled its purpose.

Thor’s stomach drops. His mouth falls agape in sudden horror, though no sound escapes him. 

This cannot be, this cannot— 

He barely registers the lightning sparking from his limbs as he tries to cup what he’s certain is Loki’s remains in his palms, the silvery, almost violet liquid rolling off his skin like oil. There’s too much, he can’t possibly carry it all. 

“No, no, no— damn it Loki, damn you—” 

Thor’s hands are shaking, his heart juddering in his chest as he looks around frantically for an empty vessel. If only he can get enough of Loki to the healers, maybe he can still save him, maybe he—

Thor’s breath catches in his throat as the liquid suddenly seems to come _alive_ , starting to move of its own accord. What remains on the table begins to coalesce, flowing across the marble. Thor looks around and realizes with no small shock that there are droplets of silver converging from all over the room— rolling up the legs of the table, dripping down from the ceiling. 

After a moment, Thor hesitantly lowers his cupped palms back to the table, and the quicksilver in his hands quickly flows down to merge with the larger puddle on the table. There must be thousands of droplets flowing from all corners of Loki’s study, and slowly the puddle grows larger and larger until, finally, it seems to lie still.

Thor holds his breath. The puddle remains motionless for a long moment. No more stray droplets. Just… nothing.

And then it sits up.

Thor is frozen, entranced as the shimmering entity slowly takes an amorphous shape. It’s still no more than a blob, but it almost seems to take stock of its surroundings— as if Loki is still sentient in there, somewhere.

“Loki,” he finds himself pleading. And then the words fall out of him in a rush. “Loki, it’s me, I’m here, you’re safe. I’m sorry, brother, I’m so sorry, I can’t—“ He feels his throat choking on the words. “Loki, it’s me. It’s Thor. Please, Loki. Answer me. Can you hear me?”

The entity seems to respond, turning to him. Thor holds his breath once more as he reaches out a hand. This time, the strange liquid glides up onto his hand, wrapping around his wrist with a spray of delicate tendrils that seem to sprout from nowhere. 

Thor gapes. 

In its semi-solid state, the strange entity has strength enough to climb. And instead of the oily texture from before, now it’s almost _soft_. It looks wet and a bit shiny… yet feels impossibly, velvety smooth in a way that should be uncanny but somehow isn’t. Almost like the slippery hide of a starfish, the functioning part of his mind supplies. Or a salamander. Or polished metal, come to life.

And the color… It looks silver one moment and lavender the next, shifting in the light like oil on water. Like the patina on Loki’s silver vial. Thor realizes he cannot tell if it is warm or cool and a shiver runs through him. 

“Loki,” he tries again, a note of panic in his voice. “Tell me! How can I help you? What must I do?”

The liquid seems to be… listening now. It seems to ripple in response, but Thor cannot make sense of any of this. He wonders if the liquid can feel the tremor in his hands. Cold dread creeps up his spine.

“Don’t worry,” he begs. “It’s going to be okay, it’ll be alright, brother. I’m taking you to Eir, just hang on.”

But before Thor can even take two paces toward the door, the liquid becomes— well, agitated is the only word for it— and then it’s suddenly oozing up his chest, gripping and clinging to him with those sticky shining tendrils, thicker than before. He instinctively panics, even though the rational part of him hopes, _knows_ this is somehow still Loki.

He blinks and the liquid seems to seep into his clothing and disappear.

Thor freezes once more, assessing his next move, but then— a strange sensation washes over his whole body and he suddenly feels faint. Drops heavy to his knees, sweating hot and cold as his insides seem to rearrange themselves, and _oh_ , what in Bor’s blood is going on—

_Hush, Thor, it’s alright. It’s just me._

It’s only then that Thor realizes he’s been making a strained, high-pitched noise in the back of his throat. 

“Loki?” He gasps, the strange feeling receding slightly, but he feels… different. Woozy. And where is Loki’s voice even coming from?

_I’m in your head. Don’t go to Eir, she won’t have the slightest idea how to deal with this. And besides, imagine trying to explain that you interrupted me at work and now I’m inside you._

“Inside me?” Thor protests, even as he knows it to be true. “How—?”

_I don’t know for certain, I only have a working theory. But I thought it was worth a shot, seeing as you couldn’t understand me as I was. At any rate, I do appear to be somewhat intact— thanks very much for your concern, considering this is entirely your fault. And for Bor’s sake— you just saw me get dissolved by a strange exploding liquid and your first inclination is to run over and_ try to pick it up? _Gods, it’s a wonder you’ve made it to eight hundred._

It is unnerving, yet oddly comforting to hear Loki’s rant coming from inside his head— a far more intimate version of an already familiar phenomenon. Thor decides to sit down in one of Loki’s less detritus-coated armchairs, rubbing his hand over his eyes. He is no stranger to bizarre surprises, not after his many years spent abroad in other realms and worlds— not to mention, a lifetime of living with Loki. But this particular situation is not one he’s remotely prepared to deal with.

“I’m glad you’re all right, brother,” he says, and means it. “But what must we do? How do you get your body back?”

_Ah,_ says Loki, and Thor thinks he sounds a little peevish. _Now that is a fine question… we may need to set my room to rights first._

“Can you see through my eyes?” Thor asks, grasping at a course of action.

_Yes. I perceive everything that you do, and then some. As per usual._

Thor ignores the dig at his intelligence. “So, if we fix your room and find some book of yours that tells you how to reverse the effects, you’ll be able to read it and tell me what to do?”

_In theory. The thought has already crossed my mind. But I am highly doubtful of such a simple solution laying in wait. I have read my entire library many times over and I don’t recall ever seeing a corrective for that specific type of working going so wrong as this. Here, look closely at the table so I can see exactly what was affected._

Thor gets up and steps back over to the table, gingerly runs a hand through his hair but doesn’t dare interrupt. Loki muses in silence for a moment before he continues.

_Yes… I see it now. I’m pretty sure that in my body’s instinctive attempt to counteract the dissolution spell, it may have slightly overcompensated… You haven’t seen that silver vial anywhere yet, have you?_

Thor frowns, for he hasn’t. And he doesn’t like where this is going. “Why?”

_As I said, it’s just a theory, for now. The enchantment on the vial was supposed to withstand the effect of the potion, so under normal circumstances I would have been the only thing affected by the spill— but I felt my seidr pull at its protective charm as the potion began to work upon me. I think I may have subconsciously transferred the enchantment in an attempt to use it to contain the damage to my person, which left then the silver vulnerable to the potion’s effects. Hmm..._

Thor gapes at him. Well, at the empty air. “So what you’re saying, brother…” He hadn’t wanted to believe it, but he’d felt that itch at the back of his mind when he first saw the liquid and how it behaved. Of course.

Loki sighs. _Yes. I have evidently bonded with the vial. Which might partially explain my… unusual appearance. But on the plus side, it appears to have helped save my life. So there is that._

Thor gives a slightly hysterical laugh. “How is that even possible? That shouldn’t… that shouldn’t be allowed to happen. Can’t you just... change back?”

_It’s not that simple,_ Loki groans. _I tried, when I was sitting on the table, but I’d already sensed it was going to be futile. The enchantment may have helped protect my physical form, but I’m certain the only reason I’m still sentient is that my body shapeshifted in order to keep me intact through the dissolution process._

Thor sighs, rubbing a hand over his beard, frowning when he realizes it has been singed. “So when you shifted…” he prompts, not liking where this is going.

_The problem is that my molecules and that of the silver vial had already been intermixed, and evidently my body, being under siege, couldn’t tell the difference until it was too late. That shift in molecular structure hampered my ability to take my usual form, so instead my body evidently found some sort of… common denominator._ Loki gives a small, strained laugh. _Thank the Norns I was wearing garments woven of seidr today. I might have appeared as a leather boot._

Thor grimaces. “So now you’re just... stuck like this? Haven’t you ever been less than solid, before?”

_Of course. Were I to shift into a liquid of my own accord, then shifting back would pose no issue. I can turn into anything as long as it’s me._

“But you’re not just ‘you’ right now...” Thor acknowledges, wearily. “And now you’re… inside of me.”

_And the protective enchantment wasn’t the only thing woven into the silver— there were others as well. Probably nothing harmful, but it’s all one big mess._ Thor can almost sense Loki rubbing his forehead and sighing. 

_My theory that I could dissolve myself enough to be absorbed into your form has proven to be correct— though that obviously isn’t a sustainable solution. No doubt I can reassemble myself back into the semi-solid state you saw a minute ago. But that won’t fix the greater issue._ Loki paused, seemingly lost in thought for a moment. _If I am to regain my own true form, I will need to find some way to correct the fact that I intermixed and bonded with a magical foreign substance. That might involve another potion. Or maybe a series of spells. As I said, I don’t believe I have ever read of this happening before in such an unusual manner._

Thor lets out a low whistle, a feeling of dread upon him. “So you’re telling me you don’t know.”

There is a moment of hesitation. _I have some ideas. But nothing… nothing certain._

Thor nods, hands on his hips, taking stock of the room and of the fact that his brother is currently an amorphous liquid being residing inside his body. 

Yes, this is fine. This all is just perfectly normal and fine.

“It’ll be alright, Loki,” he reassures his brother, with confidence he doesn’t feel. “I know you’ll figure it out. We’ll have you back in your skin in no time.”

Loki’s voice sounds weak when he answers, _I wish I shared your confidence._

In the end, they spend many hours poring over some of Loki’s more illicit magical tomes and grimoires, all to no avail. As Loki predicted, there doesn’t seem to be a specific reversal for this particular situation, in part because Loki suspects that most Asgardian and Vanir sorcerers were not shapeshifters. The few who were presumably had not often been interrupted in their attempts to brew delicate dissolution potions by oafish brothers.

They do manage to draw Loki back out of Thor, returning him to that strange semi-liquid state. Despite having already established telepathic contact, they once again seem to be unable to communicate when they are separate, even when they make skin-to-liquid contact. It puts a bit of a damper on things, as Thor realizes this probably means Loki will have to remain inside him as they figure out a solution. 

Perhaps it’s for the best, he reflects. Imagine their parents finding Loki like this. There’s something deeply unnerving about seeing his brother as a shimmering, amorphous being — although, that said, it now appears that in addition to extending tendrils of varying sizes and shapes, he can take on other rudimentary forms. Thor watches Loki try to form a more humanoid shape, but he appears to be struggling and gives up after a few tries at standing upright.

After some time of this, Thor suffers Loki climbing back onto his chest, sighing heavily. This exchange doesn’t require words. Thor nods his assent, bracing himself, and Loki seeps back into him. It’s not nearly so painful this time, now that he knows what to expect— but it is odd, thinking of Loki making room for himself inside of Thor. A shiver runs up his spine but then the feeling passes.

_Well. That was extraordinarily humiliating. I don’t think I much care for that form,_ Loki remarks, clearly not pleased with his minor progress. _I still have my seidr, praise the Norns, but my shifting abilities feel all strange, like I can’t quite remember how to do it. Like the muscle memory is gone…_ He huffs. _Even the most magically-conductive silver is not suited for this._

Thor sighs, sitting back in Loki’s chair and looking around the much tidier study. (Luckily, Loki’s remaining seidr was enough to put it to rights and restore his charred books.) Thor doesn’t have much to offer in the way of feedback when it comes to shapeshifting— his own magic is something far more intuitive and elemental. The only thing Loki’s managed to teach him in nearly a thousand years is to disguise Mjolnir and to use her as an anchor to summon his armor. Shapeshifting and potion brewing are still quite beyond him. Loki’s been explaining it all well enough, but he feels utterly useless and it saps the energy from him.

“I’m famished,” Thor realizes. “Aren’t you?”

_A little,_ Loki admits. _Gods, this is strange. I don’t even know if I can eat like this._

Thor just laughs, the absurdity of the situation finally sinking in. “Well. Looks as if I’m eating for two. I suppose I’ll inform everyone that you’re in the middle of a very important experiment and are not to be disturbed?” 

_Said without an utter trace of irony. Ah, what an utter joy it is to be stuck inside your head._

“But you’re not just in my head, are you…” Thor mutters. “You’re everywhere. I can feel it.“

Loki is silent for a few moments.

_Have my supper sent to my rooms,_ he finally replies. _That will arouse the least suspicion. You can take care of it later._

Thor nods in reply, then feels foolish for doing so. But he supposes Loki can tell what was meant. “Should we try the library after supper? And— wait a minute, how am I going to speak to you in public?”

_Well, I_ am _in your mind… I suppose you could try thinking directly at me. It might take a bit of practice._

Thor tries. All he garners in response is laughter. 

_Well… I think I got the gist of that. You’re wondering why I couldn’t have turned myself into a toad? I think that should be obvious: toads are far more your domain, brother. I wouldn’t want to encroach._

Thor laughs, shaking his head as he stands and closes the heavy book in front of him. At least Loki is once more in a jovial mood— for now.

“Come on,” he says aloud. “I’ll practice more, but after food.”

A curious thing happens while he— while they— are eating. Thor chews and swallows dutifully, trying to maintain a normal conversation with their parents as if he isn’t currently acting as a vessel for his brother’s disembodied spirit. He takes a drink of his wine, and it’s then that he feels it— something cool and almost wet on the inside of his wrist, inside his sleeve. 

Thor glances down and sees a little tendril of metallic quicksilver curling around the inside of his wrist.

_LOKI._ He manages to shout inside his head without saying anything aloud, but just barely. _NO._

_What? Oh… dear. I did not intend to do that._

The tendril retreats back inside Thor’s sleeve, thankfully having remained hidden from Frigga and Odin. He hopes.

_What. Happened._ He thinks, hard. Trying to ensure his message comes across accurately. _I saw you._

He gets the strangest sensation that Loki is shrugging. _I think watching you hold the glass, it just felt so natural, as if it was my own hand… I’ll attempt to rein it in. Mother’s watching, look sharp._

“My son, are you well?” Frigga‘s voice is full of gentle concern and Thor turns to her with his best expression of cheer. 

“Yes, mother. Apologies, my attention drifted for a moment.” At least that wasn’t a lie. But when she doesn’t seem fully satisfied, Thor finds himself embellishing. “I was just recalling some training exercises I would like to practice tomorrow morning.”

This seems to do the trick, and she smiles at him. “You and your brother are so much alike at times. Always preoccupied with what lies ahead.”

Thor knows she speaks of Loki in the abstract, but the thought that she somehow can tell what they’re up to makes him want to squirm under her fond gaze. He almost wants to come clean, tell her exactly what’s going on.

_You’re doing well, Thor,_ Loki cautions, sensing his mood. _Don’t cock it up now._

_Why shouldn’t we tell her?_ Thor wonders, spearing another slice of roast pheasant even as he grins back at Frigga. _Maybe she can help._

“I wonder where we get that from,” he teases aloud, hoping to distract with a bit of humor. 

_Do you not understand?_ Loki isn’t even trying to hide the disdain in his voice. _This isn’t proper, it’ll only make us both look bad in their eyes. Mother will be more forgiving, but do you really want Father to know? Do you want the whole court to whisper?_

_I wasn’t actually going to tell her,_ Thor thinks, grumbling internally. It’s getting a little easier to speak like this, but now he’s realizing the true difficulty lies in not letting it show on his face. This is going to be more challenging than he realized.

The conversation around Thor turns to an upcoming court visit from Frigga’s distant relatives, and he tunes out once more, focusing on eating enough to sate his hunger and leave as soon as possible.

_Well, if it’s of any interest to you, I do indeed feel as though I have been fed and watered,_ Loki is musing in a sort of detached, academic tone Thor is well familiar with. _This would be rather fascinating if it wasn’t so inconvenient._

“Yes, very fascinating indeed,” Thor says, and realizes he’s spoken aloud only when Odin and Frigga shoot him a confused look. 

“You’ve never before taken an interest in banquet-planning, my son,” Frigga remarks, clearly surprised. “Although I suppose, if you wanted to be more involved…”

Odin scoffs at this and Thor nearly blanches. “Ah, I spoke merely in appreciation, Mother,” he tries to recover.

_It is an art quite beyond me,_ Loki whispers in his ear, and Thor seizes the lifeline, repeating his words: 

“I meant only to convey my admiration for the amount of strategy involved. It is more tactical than I had perhaps realized.”

Frigga smiles and gives him a gentle nod, though there is still something in her keen gaze that tells Thor he’s not entirely out of the woods. 

_Good save. Though you’d better not speak to me anymore without practice. I can hide from Mother and Heimdall, but we don’t want her getting suspicious,_ Loki cautions. _We should go. Make an excuse._ Thor agrees, doesn’t dare to reply.

Meanwhile, Odin snorts, shaking his head.

“My Queen, I daresay Thor has much on his mind and that taking an active hand in court visits is the very least of it.” He shoots a different kind of keen gaze in Thor’s direction. “One day he may be so lucky to have a wife with your talents.”

_Get us out of here, you buffoon,_ Loki hisses. 

Thor bows his head toward Odin, hoping to infuse the gesture with enough deference to allay suspicion. “Father, Mother, if I may beg your leave— I regret I have duties to attend.”

“Yes, yes, go on…” Odin waves his hand carelessly. 

Thor kisses his mother’s hand, though he only dares meet her eye for a moment before he sweeps out of the room, the hand hidden from their parents clenched tight into a nervous fist.

He’s only taken a few strides down the main hall when suddenly the world begins to spin and Thor stumbles, pushed forward by some unseen force. He catches himself on the edge of a wooden table that wasn’t there a moment ago. The legs screech along the stone floor in protest. His heart races at the sudden shock, but a quick glance around reveals he’s in a familiar setting. 

Loki has taken them to one of the private back rooms of the library, full of books on sorcery and other somewhat illicit subjects— a place Thor rarely visits except to seek out his brother. In fact, very few others ever dare venture here. It is an extension of Loki’s study in everything but name.

Thor takes a ginger breath. He doesn’t sense anyone in the common area beyond the door, not at this hour.

“Loki?”

There is no response, but Thor can feel his brother’s emotions running wild, humming through him. It’s all in a tangle and he can’t really understand why Loki would be so worked up.

_Loki, are you okay?_ He asks, trying again. _I don’t think they really suspected anything..._

_I’m perfectly fine,_ Loki snaps, then seems to realize he sounds rather less than fine. His voice is considerably more collected when he speaks again. _Focus, now. I don’t want to be stuck like this any longer than necessary._

With a strange sense that he had, as usual, said the exact wrong thing, and with no idea how to fix it, Thor decides there’s nothing for it but to let Loki wallow as he usually does. 

He lets his attention turn to the many bookshelves, overflowing with a cascade of ancient magical tomes. They are at least two or three times greater in number than the collection in Loki’s study. He steels himself for an evening of rigorous boredom.

“All right. Where do we start?”

Hours pass. Naturally, there is no breakthrough. 

After a long and fruitless search into the early hours of the morning, they finally admit defeat and return to Thor’s chambers. He strips off his clothing and falls into bed, exhausted mentally more than anything else.

“We’ll figure it out tomorrow,” he says with more confidence than he feels, beginning to drift off. 

His brother sighs. _Goodnight, Thor._

“Goodnight, Loki.”

The days crawl by and there is no sign of a means to return Loki to his usual state. Thor labors in the library— a decoy volume of Vanir military tactics at the ready, just in case anyone comes to ask what he’s up to— but nothing he or Loki can track down seems to hold any promise. All the solidification spells take for granted that the substance being returned to a solid state is meant to cohere together— the very last thing they want.

The one thankful thing about Loki being a noted recluse is that it’s far easier to hide his absence than Thor would have expected. He still has the ability to conjure doubles to fool the maids when they come to clean his quarters, although he proves unable to generate his usual levels of magical energy and soon has to begin siphoning off Thor. (“Never thought I’d make such a good battery, did you?” _Oh, do shut up._ )

They continue to have Loki’s meals sent to his rooms, which are conveniently attached to Thor’s chambers by a private corridor. Thus, Thor takes care of eating for both of them— for as it turns out, he does have nearly twice his regular appetite. Loki has ever been lean in build with a fast metabolism, and even in this state, he needs a significant amount of energy. 

They soon find that Loki grows frail when he’s too far from Thor. A half hour is perfectly fine. A full hour is less than ideal, but manageable. But after half an evening, he becomes dangerously weak. One night, he nearly drains Thor into a faint when they reunite after Thor spends a few hours drinking with the Warriors Three. Luckily, Thor comes to and manages to drag them to the kitchens for an emergency midnight meal. 

After that scare, they decide it’s best to allow Loki to remain within Thor as much as possible.

Thor doesn’t know exactly how Loki’s feeding off him; he’s not sure Loki even knows. Either way, he decides it’s better not to ask. And he feels safer, knowing that Loki is there inside him, where he can take care of him. He’s still wracked with guilt that he almost let Loki waste away without him— it was Loki’s suggestion, to leave him behind, but after almost losing his brother twice in the past week, Thor is no longer willing to take any chances.

They do manage to achieve a modicum of privacy— with Loki slipping out of Thor to rest on the bed or the desk as Thor attends to his daily ablutions. Thor knows his brother is a creature of habit and the lack of ability to groom himself is probably yet another frustration, but there’s really nothing for it at the moment.

When Thor is required to attend to his business on the training grounds, at council, or with his friends, Loki now tags along within him. He’s rather helpful at council meetings, suggesting sensible things for Thor to say and whispering advice— though he gripes that now the councilors will think Thor far more wise than he truly is. Thor doesn’t know how to adequately thank him, not in a way that he won’t see as mockery.

And true to form, Loki has redoubled his usual attempts to get Thor to laugh at his snide comments. Thor catches Sif giving him an odd look once or twice over their pints when he snickers at Loki’s half-inebriated remarks about the other denizens of the pub. He’s in a good enough mood that he isn’t concerned about anyone noticing him laughing at nothing, even as Loki scolds him for doing the very thing he was trying to trick Thor into.

When Thor wanders back to the palace that night, loose-limbed and at ease, he feels Loki’s drunkenness right alongside his. He feels warm, happy. Unguarded enough to announce aloud, 

“I’m glad you’re here with me.”

He doesn’t say Loki’s name aloud, to avoid another scolding. But he feels a lazy curiosity stirring in the back of his mind and knows he’s got Loki’s attention. 

_Are you now._

“Of course,” Thor says jovially, ducking under a low-hanging branch as he diverges from the road and takes a well-traveled but well-hidden path that will lead him to the palace the back way, through the royal forest and their mother’s gardens. “Do you remember this place?”

It has been some time since they have walked this way together. Thor’s friends usually prefer to take the open road, as it’s hard to wind through the mossy boulders and undergrowth with a full party and carry on conversation. But he and Loki used to take this way when sneaking down to the village as boys— Loki disguising them so they could drink in the pubs or see the traveling players and burlesques without anyone batting an eye.

_I’m only the one who showed it to you,_ Loki reminds him, but there is no annoyance in his voice. Merely fondness. _Do you think the tree is still there?_

Thor doesn’t have to ask to know which tree he means. It’s just a little way further, and when they reach it, Thor ducks under a wayward branch to inspect the trunk. It’s covered in thick, spongy moss that feels cool and soft under his fingers, damp with the night air. Thor peers at it, trying to move so he isn’t blocking the moonlight, but then a soft green witch light appears over his shoulder and he smiles.

It has to be here—he’s certain of it. Just covered in a layer of moss. Thor removes his paring knife from his boot and delicately cuts away a circle, pulling the moss free. He wipes the dirt from the bark, and there it is— their carving from back when they were just barely four hundred. 

“Thor was here” it reads, in Thor’s bold carved runes, and then below, in Loki’s far neater hand, “Only thanks to Loki.”

Thor laughs at the sight, remembering Loki’s smug little face. He’s pretty sure that episode had ended in a brief tussle before they’d run through the boulders, whooping and hollering, followed by a naked jump into the ice cold stream. Thor runs his hand over the carvings, softened now by the centuries. One day the great tree will swallow them up entirely.

_See? There’s your proof._ Loki is saying, and Thor smiles to hear the nostalgia in his voice. It suddenly seems to him as though he and Loki have not been this close in many, many years.

Well… never _this_ close, granted. But these past few days, Thor has found himself reminded in myriad ways why he so loves Loki’s company; how greatly he misses him when they’re apart. Thor knows he’s far from blameless for letting them grow apart— there were _reasons_ for that. 

But that was exactly why he’d been hanging around Loki’s study in the first place. Seeking out his company. Thor has missed his brother desperately these past several decades, as their growing duties took them in opposite directions. (At times, he fears, he has missed Loki perhaps too desperately.) 

And he can’t deny that he sort of enjoys this strange excuse to spend so much time with him. To protect him and care for him. It’s not selfish if it’s helping Loki stay alive, surely. It’s symbiotic. That’s all.

“Do you want to go for a swim?” Thor finds himself asking, and he can feel Loki’s disbelieving laughter reverberating through him. 

_A midnight swim? You’re a madman, it’s surely freezing._

Thor shrugs, giving the tree one last glance before wiping his knife on his breeches and tucking it back into his boot. He steps back toward the trail, straightening to his full height. The witch light follows him, even though the moonlight is brighter here, and he smiles at Loki’s consideration. 

“Why not? You’re not bothered by cold.”

_I speak only out of concern for my dearest foolish brother._

Thor laughs again, and his chest feels light and warm. “Then swim we shall.”

It only takes him a few more minutes until he can hear the stream, and another moment more before he summits their favorite rock; a massive boulder rising high above the bank. He can see the water now, pale and rippling, tossing flecks of silver in the wet light. It makes him think of Loki. Of the silvery tendril curling around his wrist. Of all the times they swam naked under the moon here together and slept out on the banks next to an enchanted fire, watching comets and talking until they fell asleep. 

An old, familiar yearning surfaces in his gut— one that he’s not too drunk to recognize. Thor shoves it down out of habit. The cold water will distract him.

Loki is quiet as they look around for a moment, and then Thor is stripping off his gauntlets and armored breastplate, then the tunic underneath. His boots, winingas and breeches follow, and then he’s bare under the moon, skin prickling in the cool night air. He feels free here, in the wilderness. Everything weighing on him seems to suddenly dissipate.

_It’s so still,_ Loki observes, and his voice feels reverential and hushed. _I’d forgotten how beautiful this place is._

Thor nods. He hadn’t consciously set out to give Loki some relief from the stress of his predicament, but it seems like this may be doing them both some good. “See? Aren’t you glad you had no choice but to come out with me?”

Loki just snorts, dismissive. _Are you here to swim or to gloat?_ And before Thor can reply, Loki’s taken control of their legs and they’re running, leaping from the high rock and Thor is laughing, laughing, laughing even as they hit the water.

He surfaces with a mighty gasp, whipping his head around. Wet hair sticks to his face and he wipes it back, blinks the water from his eyes. He looks around for Loki out of habit before he remembers. 

“You’re a bastard,” he jokes, treading water. “Also, congratulations, it’s really fucking cold, in case you can’t tell.” Loki just chuckles, seeming a bit breathless from the plunge himself. 

_I have to get my thrills somehow,_ he remarks, droll as ever. _Race you to the far rock._

It’s the strangest feeling as Loki propels them forward with a graceful breaststroke that Thor is certain he couldn’t replicate if he tried— yet his form takes to it as naturally as if he were Loki. His brother has always been at home in the water.

_You’re mad,_ he thinks, and he feels Loki’s glee. 

_Am I?_

“Yes,” Thor says, when they reach the rock. “But I think it works for you.” He watches Loki slip free from his chest, sliding down his arm to rest on the boulder. His silvery-violet form undulates gently, like seagrass under the waves, and Thor is entranced for a moment. Before he can think better, he reaches his hand out to stroke its side. The impossible texture is as slick and smooth as always, that odd warm-cool temperature. Despite Loki’s fluid, ever-shifting appearance, he feels surprisingly solid underneath, coiled and powerful. Then Loki seems to ripple, or perhaps tremble, and Thor comes back to himself.

“Forgive me,” he says, automatically. “It’s just so strange, seeing you like this. And yet… why not? You’ve taken so many forms over the years, why should this be any different?” He pauses. “I mean, the lack of a face is a bit of a departure.”

Loki ripples once more, and Thor wonders if he’s trying to speak, but then he begins to shift and Thor can almost make out a familiar grinning face before the quicksilver collapses back in on itself. He smiles, holding out his hand palm-up.

“Want to see if you can swim like this?” he asks.

He swears Loki is looking at him and smirking. He flows up onto Thor’s arm, tendrils curling around his shoulders with that oddly powerful grip, then down his other arm into the water. Thor watches, rapt, as the silver spreads thin over the surface of the water before condensing again, playing amongst the ripples and the gentle rapids of the stream. 

Thor doesn’t let him go far, worried about losing him, but soon they’re swimming together, and it’s only a few more minutes before Loki manages to take on the form of a ray— apparently that’s simple enough to hold— and Thor marvels as he dives below the water, his pale form reflecting the light even as he nears the bottom.

Thor takes a breath and dives down after him, following him into the dark. 

They surface a few minutes later and Loki flows back up to Thor’s chest, clinging to his skin, staying on the outside of him. Thor backs up onto a boulder and puts a knee up, taking a break from the frigid water. His wet, goose-pimpled skin shines pale in the moonlight, but it’s nothing compared to Loki— his brother slips down his arm to rest on his propped-up knee. His shimmering, marbled surface looks even more violet in this light, and as Thor stares into it, he realizes it’s almost like looking into a nebula, seeing more layers the longer he stares.

He gets the distinct sense that Loki is staring back. It is quiet save for the murmuring of the stream and the faint sound of crickets, the occasional hoot of an owl.

“I saw you shift,” Thor says after a minute, nodding toward the water. “You’re getting better at it.”

Loki’s form undulates, possibly in agreement— or self-deprecation, if Thor knows his brother— and then flows down over his leg, back up over his bare torso to his chest. 

It’s the velvety sensation of Loki gripping his abdomen with a hidden strength— not unlike the muscles of a snake, he realizes— which stirs Thor’s blood in ways it ought not to. He sits up as casually as he can, trying to keep any more of his body from reacting. 

“Want to take another dip?” he asks, trying not to sound too urgent. 

Loki seeps into his chest— and Norns, it’s still intense, feeling and watching it happen without his clothing in the way. Silver tendrils seeping into his skin, which would look golden tanned in any other light. It’s mesmerizing, watching their forms become one; strange, yes, but so natural, as if they were meant for this.

It doesn’t hurt anymore, either. It’s as if Thor’s body is ready all the time, now that it knows how to make room for Loki. Just all that warmth and the sensation of... fullness, it dawns on him. It’s fullness that he feels. As if myriad unseen parts of him were empty before and he never realized, until—

_Alright,_ Loki’s voice breaks through his thoughts. _But if you take too long, I will make you jump again._

“Do your worst,” Thor challenges in a rough whisper. In the space of a breath, they’re backing up on the rock, muscles tense and ready to spring, and Loki’s launching them with a whoop into the black, cold water. 

They dive deep, sending silvery fish darting into the shadows, and Thor feels the pressure of the water around them as a gentle embrace, balanced by the feeling he carries inside of their shared body. By the breath filling their lungs.

Thor has long heard tell of Mimir’s well, where it is rumored Odin traded his eye for the wisdom needed to defeat Asgard’s foes. And as boys, he and Loki had begged for stories of the sacred pool that feeds the roots of Yggdrasil— a hallowed, dangerous place where only the bravest of champions and the most foolish of knaves dared venture, attempting to divine the will of the Norns. Often, the stories ended with both the hero and the fool getting far more than they’d bargained for. 

So it is perhaps no great surprise that this ancient mountain stream, sacred to none other than the two of them, should have its own secrets to whisper in his ears.

Floating at the bottom of the river, feet just touching the sand, Thor looks up toward the moon and thinks to himself, quite calmly, that it’s very possible he might be in love with his brother.

**Notes for the Chapter:**

> Winingas are the (usually) woolen strips of cloth used by Vikings to wrap the lower legs. Thor is often seen to be wearing them or something similar.


	2. Chapter 2

**Summary for the Chapter:**

> Thor feels his cheeks flush against his will. “I wasn’t lying, you twit.” In an attempt to hide one secret, he sacrifices another. “I just haven’t allowed anyone else do the honors…”
> 
>  _Really,_ Loki drawls. _I must say, I’m a bit surprised. Adventurous lad like you… Not even Fandral, truly?_
> 
> Heat is rising to his chest now, and Thor knows he is flushing there too. But he can sense a different heat deeper still, in the very center of him. Anticipation.

The next morning comes with its own surprises. Thor wakes slowly, groggily, barely thinking, until he hears the amused purr in his mind.

_Good morning, brother._

Well, now he’s definitely awake. Last night comes rushing back— the pub, finding their tree, the late night swim. His… epiphany. Ah. Right.

“Loki,” Thor groans, rubbing a hand over his eyes, wiping the sleep from them and willing his heart to stop racing. “How long have you been awake?”

_Oh, not too terribly long. It’s not very exciting to be up while you’re sleeping. I would have woken you sooner, but you seemed to be enjoying your dreams._

Thor frowns. “I don’t recall what I dreamt.”

_Well, you appear to have erected a monument in its memory._

Thor sighs, shaking his head. “You are impossible.” He sits up against his pillows then stretches and scratches his shoulder, noting that he is indeed sporting a rather respectable hard-on. At least he has a convenient excuse for its presence. “I’m sure it will go away shortly.”

 _Nothing short about it,_ comes the sly remark.

“Oh, to be able to throttle you right now.” Thor attempts to hide his embarrassment with an exaggerated growl, running his hand through his unruly hair to keep it off his face. Sleeping before it had fully dried from their swim hadn’t been his brightest move— nor was sleeping in his breeches. But Loki wasn’t finished.

_Why throttle me when you could be throttling the bilgesnipe in your trousers?_

Alright, that was it.

“You know what? You’re right,” Thor says smugly, reaching down to palm his erection. “Maybe I will just take care of it.”

 _Oh, by the tree— I was only joking,_ comes the reply, but Thor isn’t having it.

“Oh no, you’re absolutely correct. Waste not, want not,” Thor continues blithely, starting to work his cock into proper wakefulness. Two could play at this game. And perhaps then he could get rid of this little problem right under Loki’s nose without admitting to any other motives.

_You are actually the worst._

“That’s not what they usually tell me. They usually say, ‘Thor, that was incredible and we should do it again sometime with two of my most buxom friends.’”

 _I utterly loathe you,_ Loki says, but he still hasn’t made any move to vacate Thor’s body.

“No, you don’t,” Thor says easily, deciding not to remark any further on Loki’s choice to remain.

But the joke is on him, because having Loki currently inside him proves to be incredibly distracting. For one, he keeps a running commentary insulting Thor’s technique. 

_Why aren’t you using oil?_

“I’m not ready for it yet. This is how I do it.”

_Barbarian._

“What, you use oil right from the beginning?”

_Well, I’m not a fucking heathen, am I._

And then,

_You shouldn’t go so fast so soon, it’s much better if you keep it slow. Where’s your sense of pacing?_

“Whose cock is it, Loki?”

_Alright, alright… someone’s touchy._

And the worst,

_Honestly, brother, I’m beginning to doubt everything I have ever heard of your prowess. What is this artless technique? This is the work of a rank amateur._

“I swear to Ymir—”

_I must say, I do pity you so. I presume you don’t even know how to find your own prostate._

“Of course I know about that, you idiot,” Thor growls. 

_I didn’t say ‘know about’, I said ‘find.’_

Thor rolls his eyes. “Look, I know how to find it. Right now, I’m just trying to get rid of this thing and you’re making it very har— you’re making it very difficult to concentrate.”

 _Oh dear,_ Loki says, not sorry at all. _Well, why didn’t you say so? Let me be of assistance, to atone for my terrible rudeness._

Before Thor can ask Loki what he’s planning on doing, he feels a sudden bloom of pleasurable heat deep inside him. It makes him shudder and groan aloud before he can stop himself— wait, no—

“Loki!” He hisses, instantly scandalized. “Quit it!” As if they hadn’t already crossed enough boundaries, the last thing he needed was for Loki to be ‘helping.’ That was something he wasn’t entirely prepared to process.

 _Ah, so you_ are _familiar. And here I thought you were lying to save face._

Thor feels his cheeks flush against his will. “I wasn’t lying, you twit.” In an attempt to hide one secret, he sacrifices another. “I just haven’t allowed anyone else to do the honors…”

 _Really,_ Loki drawls. _I must say, I’m a bit surprised. Adventurous lad like you… Not even Fandral, truly?_

Heat is rising to his chest now, and Thor knows he is flushing there too. But he can sense a different heat deeper still, in the very center of him. Anticipation.

“My ‘adventures’ are none of your business,” Thor growls again, trying to focus on getting himself off as soon as possible. 

He doesn’t need Loki to know the details. _Any_ of the details. Certainly not anything about what— and who— he thinks about when he’s adventuring. He’s already nervous enough that Loki might be able to somehow sense his thoughts and he’s been trying very hard not to think of anything incriminating. Nothing from last night, for starters.

And he’s especially not thinking about how the place Loki had roused is now aching for more… though it’s almost guaranteed that Loki will be able to sense that much. This has become a rather precarious position and he really should have known better than to try and beat Loki at his mind games. His home court advantage has become a rather large liability.

_Oh dear, have I upset._

“You know exactly what you’re doing,” Thor mumbles, suddenly fisting his cock slower out of sheer obstinance, forgetting for a moment that Loki had told him to do so.

 _Ahh, there you go. Now you’re getting it. See, if you’d just listen…_ Loki’s voice sounds different, all of a sudden. It’s gone taut around the edges, and something occurs to Thor. He remembers Loki sliding over his abdomen the night before, the feel of those tendrils rippling over his naked skin. 

Was he goading Thor into this on purpose? Could he possibly be attempting to use Thor...

“Are you just trying to get yourself off? Using me?” Thor accuses, keeping his voice in the realm of brotherly taunting and mock-affront, even as he isn’t sure whether to be amused or turned on or slightly terrified. But he keeps his hand steady. Slow and teasing, the way Loki evidently likes it.

Loki laughs, and yes, that is definitely a breathlessness Thor isn’t used to hearing in his brother’s smooth voice.

 _Don’t be absurd. This isn’t doing anything for me, I don’t even have a body right now._

But Thor is onto him. He doesn’t react outwardly, just leans over to dispense a little more oil, slicking his cock so it makes delightfully obscene noises when he resumes his squeezing and stroking.

“What happened to you feeling everything that I feel?” Thor asks innocently, punctuating his taunt by running the blunt edge of his thumb under the crown of his prick. He can feel Loki shuddering within him, somehow, which makes him shiver in turn. “Because _I_ can feel that you can indeed feel what I feel, and therefore it’s clear that you’re lying.”

 _Fascinating analysis, brother,_ comes Loki’s snide reply. _So you’re saying we’re in a feedback loop. Brilliantly observed._

Thor just grunts at the deflection, stripping his cock faster once more. A foolish part of him wants to know if Loki will continue to interject— to give Thor directions on how to secretly please him, under the guise of fraternal criticism. For if anything will get Thor off quickly, it’s knowing that Loki might be struggling to hide his own pleasure, whatever else his motive. He doesn’t dare to hope that Loki might actually...

_For Audhumbla’s sake, Thor. You’re going to break it right off if you keep that up._

Thor can’t help it—he laughs at the sheer absurdity of their strange game. Loosens his grip on his cock. Then a truly dangerous idea comes to him— one he knows he really shouldn’t indulge, but one that may just give him a few insights into Loki’s mind. And at worst, he can play it off as a joke.

Thor barely weighs the odds before taking the plunge.

“Alright then.” He folds his arms back behind his head and looks down at his red, throbbing prick with a smirking grin. “Your turn. Show me this special technique of yours and if you impress me, maybe then I’ll change my ways.”

He can feel Loki becoming flustered, making his own heart beat faster in reply. _Don’t be absurd,_ he says, but still he doesn’t vacate Thor’s body.

“Well, someone won’t stop being a backseat pilot. I figure I may as well let you take matters into your own hands,” Thor replies, voice light and unconcerned, though his heart is racing. Let Loki draw his own conclusions.

There is a moment of silence, and then, _Fine. Just don’t be bitter when you realize I’ve bested you in yet another skill._

Thor feels a brief flare of triumph, anticipation taking hold of him before he can tamp it down. There’s that familiar yet uncanny sensation as Loki takes control of his right arm. It is incredibly jarring to feel his hand stroking himself with a touch not his own. His fingers, his wrist— they move with Loki’s mannerisms. That odd, particular grace of his. 

Thor bites his lip as he watches Loki run his thumb over the head, rippling his fingers up and down the shaft in a way that makes Thor shiver. Like the muscles of a snake.

_See. Nothing to it, if you know what you’re doing._

Thor scoffs, about to mount a rebuttal, but then Loki squeezes his prick nice and slow as he curls his wrist just so. The pressure and friction are so distractingly good as to steal the words from Thor’s mind. He watches Loki work him, the strange intimacy of what they’re doing making him lightheaded. His brother stroking his cock is not something he ever expected to witness— especially not like this— but he’d be lying if he said he hadn’t imagined—

No, don’t think about it.

Don’t think about Loki doing this to himself in the privacy of his rooms, just on the other side of that door. Don’t think about him seeking that place deep inside himself. And whatever you do, Thor, especially do _not_ think about—

_Don’t think about what?_

“Nothing,” Thor says aloud, willing his voice to remain steady. 

_If you don’t want me to know that you’re trying not to think about something, perhaps you could try shouting a little less. Norns, your brain is a noisy place._

Thor blanches, staring at the hand still moving with that slow, deliberately sensual grip on his cock. “I’m not thinking anything.”

Loki sniffs. _Well, I’m not doing this for my health, you know. Are you learning nothing?_

Thor bites his lip again, feeling anxious and exposed. The perfect, leisured friction on his cock is making his thighs flex and tremble, wringing such pleasure from him it’s almost a cruelty. He _still_ aches inside from Loki’s earlier tease, and he’s pretty sure this just Loki’s way of attempting to punish him with a slow death. It might very well be successful.

“You’re exceptionally talented, brother,” Thor offers, trying to come off as patronizing rather than admit to how weak he truly is for Loki’s touch.

 _Alright, enough of that._ Loki halts the movement of his hand. _Stop feeling sorry for yourself. The sooner I get us off, the sooner we can get back to work. Sit up._

He just said ‘us,’ Thor realizes, missing the rest of Loki’s instruction. Until more of his body starts moving without his permission.

“Whoa, whoa— Loki—“

_Calm yourself, you just weren’t moving fast enough. I’m going to do you a Hel of a big favor, and all you have to do is stay out of my way. Does that sound fair to you, brother?_

His breeches are being pushed down to the ankle, then ripped off entirely. A moment later, Loki has them rising up to their knees, spread nearly shoulder-width. 

“What are you doing?” Thor asks, somewhat nervously. It’s not that he doesn’t trust Loki, per se, but this is far different than casually diving nude into a river at night. And it’s no longer just a quick wank, efficient and without ceremony. This is him at his most vulnerable in the soft light of morning, his naked arousal at the center of Loki’s attention with nowhere to hide.

_Relax. You’re going to like this if you let yourself._

They reach for the vial of oil, coating the fingers of Thor’s left hand this time. He watches the right hand return to stroking his cock, while the left reaches around behind him.

“Loki—“ he protests, trying to stop its progress, and the muscles of his arm strain for a moment, caught between their wills. “I don’t really think—“

 _There’s no need to be_ shy _. It’s nothing new to either of us, clearly._ A brief pause. _Or is it that you are ashamed? Is that it? Do you think me shameful for embracing pleasure in all its forms, while you cower from it?_ Loki’s voice gives nothing away, but Thor knows he’d better answer carefully. Loki’s not just goading him, he’s already half-convinced Thor is judging him.

“No, not at all. Of course not,” he answers, truthfully. “I just—“

 _Do you trust me?_ Loki asks, and Thor feels a bit of his resolve crumble. Gods, but he wants it. And whatever little trick Loki just did to the head of his cock is certainly not helping him keep a level head.

“Of course, but I…” He scrambles for an excuse, hoping Loki doesn’t read the true reason for his panic, but also not wanting to insult him. “You don’t need to do this for me, brother. You don’t owe me anything.”

He feels Loki’s easy shrug in his mind. _It’s no trouble. Consider it a gift to yourself and to any future partners you might want to impress. A small thanks for allowing me to share your form._

The wording is intentional. To refuse a gift would be churlish, and Loki knows it.

Thor’s mouth contorts, deliberating for a moment before he exhales in resignation through his nostrils, slowly relinquishing control of his arm to Loki. Nothing else is said as his hand reaches back, the tips of his fingers slipping down the center of him to brush lightly over his sensitive entrance. Thor feels his thighs tremor with the sensation that it brings, and he bites his lip yet again, swallowing down an aroused noise as he tries to hold himself rigid and still.

Loki must be well-practiced at this indeed, for he keeps perfect time on Thor’s cock while teasing and playing with his ass, fingers slipping and rubbing against his flesh until Thor can’t fully manage to stifle his groan. By now, his cock is dripping eagerly onto his knuckles, and knowing that Loki can feel his eagerness makes Thor flush. He desperately tamps down the urge to rock his hips forward and back.

 _Don’t be so uptight, there’s nothing up your ass yet,_ Loki cajoles, going for droll, but Thor can hear that he’s similarly affected. He knows what to listen for now— that little exhale at the end of Loki’s sentence. A fluttering inconsistency in his tone. In the quiet of his chambers, Thor can hear his brother’s voice as clear as if he were murmuring into Thor’s ear.

The image comes to him unbidden of Loki’s firm body wrapped around him from behind, pressing his long, slick fingers to Thor’s entrance, murmuring endearments and filthy taunts in Thor’s ear before scraping with his teeth. Even more unbidden is the strange thought of those silvery smooth tendrils, slipping thick and firm inside of him, pushing their way into his mouth as Loki sucks on his neck from behind. 

The sheer filthiness of the fantasy makes Thor’s cock jerk and his face burn anew.

Loki evidently decides that’s his cue to give Thor’s cock an especially good, firm stroke as he slips the tip of a finger past Thor’s rim. Thor lets out a unsteady breath, feeling adrift, as if his body is no longer his own, as if he’s the one inside of Loki. It’s utterly surreal and he can’t help but groan low in his chest as Loki’s finger slides further in. It burns a little, having been a while since Thor’s done this to himself, but— Norns, he wants more of it.

 _Relax, brother. You’ve fought far greater foes than your own index finger and lived to tell the tale._ Loki diffuses with humor, knowing him all too well. Thor can’t resist an amused huff, and then oh— Loki has gotten his finger all the way inside him and it’s so unreal that he keeps laughing, breathless, for a moment longer.

“You have to admit, this is a bit of a new one,” Thor manages to get out as Loki begins to work his finger in and out of him, using the others to coax more oil into him. Soon, he’s set a comfortable rhythm and the burn is subsiding, the stretch beginning to feel more pleasurable than not.

Thor doesn’t know who started it, but he realizes he’s been tilting forward, pushing his ass back to better meet Loki’s thrusts, and Loki’s timing it just right with the strokes of his cock, and oh— oh this _is_ good, Thor has to give him that. Even on the occasions when he penetrates himself, Thor is normally somewhat utilitarian with his self-ministrations, preferring to get the job done and move on with the day. It figures that his brother would prefer a more luxuriant approach.

“I can’t believe you’re this self-indulgent,” Thor manages to get out in a voice mostly steady, though his breath is coming harder and faster now. 

Loki laughs, a low chuckle that sends a curl of lust through Thor’s belly. _Oh, please, you know me better than that..._

His voice in Thor’s mind is rougher, deeper than usual, and enticingly breathy. Thor can’t contain a groan. This feels so unbelievably dirty, his brother making him fuck himself on his own fingers. He’s terribly aroused, to the point that he won’t be surprised if he only has a few more minutes in him. His usual, vaunted stamina is evidently no match for Loki’s wiles.

“Ohhh—“ Thor hisses as he feels Loki press a second finger alongside the first, pulling out to work them back in together. “Have a care, Loki. My fingers are thicker than yours.”

 _Truly, I hadn’t noticed,_ Loki murmurs as they reach for the oil once more. This time the second finger slips in with relative ease. The sensation it brings is doubly intense. Thor is soon panting as Loki works them within him, curling and twisting, until—

“Fuck!” Thor throws his head back— or does Loki do it?— and groans through gritted teeth as his fingers brush the pillowy soft bundle of nerves inside him. Then again, and again. It’s not the perfect angle, perhaps, but it’s enough. His toes flex and curl and his thighs tense. He can feel his pulse throbbing strong and stiff against his palm, can feel it echoed in the tight heat enveloping his fingers.

 _I told you,_ Loki gasps now, and Thor is lost at the sound of him so affected. He rocks back onto his fingers, pushing them deeper, and Loki’s hold on his body seems to break for a moment, so Thor does the work for him and curls his fingers harder. 

The overwhelming bolt of pleasure rips breathless moans from both of them, and Loki regains his hold on Thor’s cock first, and then on the hand inside him, wresting control from Thor.

 _I’m better at it, let me,_ he insists. Thor feels sweat drip down the back of his neck. He feels hot and sensitive all over, every nerve ending at full attention. 

“Then stop slacking,” he manages to shoot back, and Loki retaliates by pistoning his fingers in and out, not as deep but hard enough that Thor’s knuckles pound against the flesh of his ass, and ohh, that’s good too, the filthy sound of it, almost feels like they’re really—

“Loki—“ he says, not thinking, but then realizes it sounds like he’s calling his brother’s name, and he quickly adds, “Don’t tease.” Which isn’t much better.

He can feel Loki’s amusement and triumph as he purrs, _Bold of you to assume I know any other way,_ before stroking over Thor’s most sensitive, aching spot once more. _But I— oh, I think you’ll agree, the results are well worth it._

Thor just makes an agonized sound. His cock is aching, throbbing. His balls feel heavy and taut. He suddenly wishes he had someone to pour himself into— to grab by the hips and rut like a wild beast. He doesn’t feel alone, per se, but he’s unused to feeling this much pleasure without a partner he can see and hold and kiss and bite— not to say Loki is his partner, no, this is just— this is just—

Loki deftly ripples Thor’s fingers up his shaft, sliding down to fondle his balls before pressing down at the sensitive spot right behind them, and Thor’s hips jerk forward into his grip as the fingers inside him press forward in pursuit.

Then he’s sinking down, down until his ass hits his heels, sticking it out to get his fingers deeper, and the shift in position feels good— and then Loki’s saying, _Ride them,_ meaning Thor’s fingers, and the fact that he specifically ordered Thor to do it… Bor’s blood, it’s so hideously arousing. 

Unable to refuse, Thor does as he says, feeling wanton and filthy, bouncing and grinding down onto his own fingers with his knees spread and his cock in his rapidly-moving fist. He can feel Loki everywhere, feel his pleasure melting and merging with his own. Thinks again of those powerful, snaking tendrils surging thick into him, holding him open and filling him up, reaming his mouth and ass without mercy.

“Mmmnn,” Thor makes a sound that’s dangerously close to a whimper and he hears Loki cry out in response, an unabashed sound of passion he’s never heard him make before.

The hot grip of desire seizes him and Thor grits out, “M’ not going to last,” just as Loki is saying, _Gods, I’m close,_ and Thor feels his brother’s pleasure growing white hot and spiraling with his own, his whole body tingling to his fingertips. He squeezes his eyes shut and feels sparks behind them, throwing back his head again as he rides his fingers hard. Ramming into the one spot that makes him see stars.

Loki makes a desperate noise that sounds torn from his throat, shaped suspiciously like Thor’s name.

Thor orgasms hard with a lusty groan, hips seizing and juddering as his cock throbs in his fist, coming more powerfully than he has in years— which is saying something. He feels Loki milking each spurt over his knuckles, arcs of warm semen splattering his abdomen, and the fingers inside still stroking deep and hard, ripping wave after wave of delirious pleasure from him.

And then even before it’s over, he feels another unexpected, mounting surge of pleasure, sharp and sweet as it blooms hot within him. Thor realizes as it seizes him that he’s feeling _Loki’s_ orgasm crashing over them both, Loki’s breathless panting and bitten-back cries echoing loudly in his mind.

It’s all Thor can do to rock his hips back and forth, trying to get his fingers as deep inside as possible to prolong Loki’s pleasure, taking over when he feels Loki’s rhythm on his cock stuttering— and oh Norns, he’s spilling again over his hand, more than should be possible after he’d just come mere seconds ago. 

But no, it’s not him— it’s Loki coming _through_ him, and Thor almost cries, overwhelmed with pleasure and agony. He hears Loki whimper in response. The spiral of arousal has them trembling and making pitiful noises for several moments more as they’re caught in its seemingly never ending pull. The last throes slowly begin to ebb away, only for one of them to shudder with an aftershock and set the other one off again.

Thor finally collapses back onto the sheets, pulling his fingers free with a low groan as he squeezes the last drips of come from his spent cock. He feels a warm haze washing over him, magnified unlike any he’s felt before— can barely believe how good that felt, how hard they both came.

Distantly, Thor feels as though he should be worried by this. Yet he can’t honestly be bothered about anything at the moment. His chest is still heaving, whole body covered in a sheen of sweat, damp hair sticking to his forehead and neck.

He wipes his brow with the back of his hand, trying to catch his breath. Feeling the come still warm on his belly. 

“Fuck…” is all he says, and he can feel the warmth of Loki’s agreement.

 _Bold… bold move, brother..._ There is a sex-drunken stupor in Loki’s voice that matches his own. 

Thor is suddenly consumed with foolish need. A desperate longing to see Loki, to try to read the expression in his eyes. To have all this, but with hips to hold, a glorious body to curl around, a mouth to lick into and a neck to nuzzle against.

Thor sighs, lazily wiping his come-splattered hand on the sheets. To his amusement, he can feel Loki’s disapproval. 

_You’re going to waste it?_ comes the admonishment, still slightly slurred around the edges.

Thor laughs, loose and gleefully surprised. “What, _d’you_ like the taste of your own? Really, Loki…” 

_Haven’t you ever?_ Loki almost sounds sleepy, which is unexpectedly adorable.

And then Thor wonders. Could it be that Loki wants to taste him? The dangerous thought sends a new frisson of arousal through him, plenty sated though he is.

“Of course I have,” Thor retorts. He nearly offers to let Loki do the honors, take control of his tongue and mouth ( _oh_ , and isn’t that a thought) but something warns him against it. It’s very possible, even after what just happened, that his brother will hesitate to do anything that he cannot somehow justify as a favor to Thor. And selfishly, he doesn’t want Loki to shy away. Not now.

So Thor drags two fingers through the come on his stomach— _their_ come, he reminds himself. Lifts them to his lips and lets his tongue slip out to lick them clean. It’s not his favorite taste, perhaps, but it’s not so bad if he thinks of it as Loki’s spend. And anyway, it’s not for him… 

Thor acts as if he doesn’t notice the little wave of pleasure, languid and low in his stomach. Ever so briefly, he lets himself imagine he’s lapping Loki’s come from Loki’s own hand. He yet fears lingering too long on such fantasies— still not knowing for certain if Loki actually wants him, or is just embracing the circumstances with his usual perverse humor.

 _You ought to eat more fruit, brother,_ comes the complaint, perhaps a little too late. And Thor remembers that Loki will often mask his delight with disdain, hide his pleasure behind criticism, and he wonders.

Perhaps, when all this is said and done, things won’t be quite as hopeless as he’d once thought.


	3. Chapter 3

**Summary for the Chapter:**

> “You’re still my brother,” Thor says, seriously, drumming his fingers on the table and staring absently at the wall in front of him. “And if you are indeed a parasite, then as your gracious host, I should be ensuring that you have all you need.”
> 
> Loki laughs again, bitterly. _So magnanimous of you._
> 
> “I mean it,” Thor says, rubbing a hand over his knee. “Parasite is the wrong word, anyway. You’re more of a… what’s the word? It’s symbiotic. You aren’t draining me. Well, except for the time where I nearly fainted, but I probably had it coming.”

**Notes for the Chapter:**

> Thanks as ever to my incredible beta, ravenbringslight. I made some significant changes to this chapter after receiving her input, so any mistakes herein are my own. And thank you immensely, sweet friends, for all your brilliant, wonderful feedback on this story. It’s become my favorite thing to write and I couldn’t be more pleased that others are enjoying it too.

It’s several days gone since their rather unusual morning interaction and Thor is gagging for release, his mind constantly drifting toward the one thing it absolutely shouldn’t be. 

He’s been sitting at the rarely-used writing desk in his chambers for the bulk of the evening, fitfully attempting to read. It should be the ideal peaceful atmosphere, for Loki has lit a fire for them and the room is perfectly cozy. Warm lamps and firelight cast their inviting glow over the rugs, the armchairs by the hearth, the massive bed piled high with furs. It’s primarily the bed that Thor’s thoughts keep returning to, but the rug in front of the fire also looks tempting...

Thor shakes himself, realizing he’s drifted off again. Attempting to read in here is clearly a mistake. Still, he can’t quite bring himself to admit defeat and he’s loathe to get up and move to the library, even if Loki can magick them there. 

He tries once more to pay attention to the tome in his hands— yet another a book of obscure spellwork that he’s already read through once. Loki’s convinced him it would be worth a second pass to see if they’ve missed anything. Thor turns a page, hoping Loki will be convinced in turn that he’s actually retaining the information.

It’s just that he has so many _questions_. 

After some deliberation, he’s privately decided that what they’d done the other morning indeed counts as sex. He simply cannot look at it any other way. They’d both been present in spirit, had given each other pleasure with Thor’s body. More to the point, Loki had taken over his body— not only paralyzing him with pleasure but overriding Thor’s control of his own limbs. And instead of recoiling in horror at this violation, this transgression of every natural order… Thor had let him do it. Had even enjoyed it.

And isn’t that the understatement of the millennium. If Thor’s being honest, it was absurdly, undeniably— but perhaps not surprisingly— some of the best sex he's ever had, if not _the_ best. And not just because of who it was with, although perhaps it’s all inextricably bound together.

Thor can still barely believe it happened, and all while Loki remained so cavalier. As if it hadn’t remotely occurred to him what boundaries they were thoroughly demolishing. In some respects, that was just Loki’s way— he would downplay the most meaningful, weighty matters and dramatize the smallest trifles. And to Thor, this is indeed a subject of great importance, one that’s thrown him into a complete spin.

He’s always thought it’d be incredible with Loki; of that, there’s never been any doubt. For centuries, he’s been certain that their alarmingly complementary natures paired with their deeply intimate knowledge of each other, all spiced with the sheer thrill of taboo, would yield a chemistry quite unlike any other. They’ve always had this… undercurrent. A subconscious tension between them, somehow both eased and enflamed by the lines they’d crossed this past week. Thor’s sure he’s not the only one who sees it, but Loki has never once deigned to recognize it, not even when he was ordering Thor to debase himself for their mutual pleasure.

Thor feels a twinge of arousal and tries to focus on the diagrams on the page, but they swim before his eyes. 

Now that he’s had a taste, he finds himself craving more. It will surely become nearly unbearable if they don’t get Loki back into his own form soon— although that will pose yet another new challenge in self-restraint, no doubt. But at least Thor will be able to excuse himself. At least he’ll be able to hide from Loki when needs must.

Thor is certain of one thing; if they continue this way, it will surely become impossible for him to hide his feelings. There’s only so much he can blame on morning wood, and there’s really no possibility of Loki remaining oblivious as to the source of his current emotional state. His brother is keen— he’ll eventually figure it out. Thor had a fighting chance of keeping his urges to himself when his mind was safely his own, but Loki certainly must suspect something now.

Norns, if this torment be the price for having a dangerously enticing sorcerer for a brother, Thor would gladly pay it twice over. Thrice, even. The problem is, he’s not the only one from whom a toll would be exacted.

Thor turns another page in the book, idly skimming with his eyes but not seeing.

What if Loki simply doesn’t feel the same? His brother often has exceptionally arcane views on seemingly straightforward matters— skillfully argues points that would never have remotely crossed Thor’s mind. And this is far from a straightforward matter. He may well have been merely taking advantage of a vexing situation. He may simply be looking to embarrass or blackmail Thor down the road for his own entertainment. He knows Loki doesn’t mean ill, but it wouldn’t be terribly unlike him to go this far for a prank. Would it? And yet if so, why hasn’t he been teasing Thor about it? Why is he not rejoicing in his victory?

Thor desperately wants to take action and broach the subject head-on. Hiding his desires suits him ill; he’s already done that for centuries, a habit born of necessity. It’s always gone against his nature to nurse his feelings in private, covering them with jovial laughter and taunts. Occasionally, he’ll erupt in actual maliciousness when he’s feeling particularly resentful and uncharitable; when Loki gets under his skin more than he can bear and Thor snaps, his anger the mighty stone wall of a fortress built to keep Loki from getting any closer to the truth. It’s in these times that he can see the shuttered look in Loki’s eyes— as if he’s reminding himself not to place hope in Thor’s goodness, if this be the reward.

Thor loathes himself for it— has always dreaded what might happen if he were forced to continue hiding for another several centuries. Worries his secret might drive an insurmountable wedge between them in the years to come, owing all to his own weakness.

But now, everything has changed. The body-sharing is one thing, but now even that most bizarre of circumstances feels diminished in comparison to the fact that he’s had _phenomenal, mind-altering sex with his brother_. 

Thor finds it ever so tempting to feel that the matter has already been settled and he has only to take. To boldly claim what should be his. With anyone else, Thor would feel assured that their desires were aimed squarely at him. With anyone else, he would not hesitate. 

But Loki is not like anyone else. And something tells Thor that being too direct will only make his skittish baby brother recoil. He can already hear Loki barricading himself behind his own wall of deflections, jokes and snide remarks; just as he’d done that morning, making it impossible to suss him out. What a fine pair they make, both taking the defensive. A war of attrition with no possible winner. Just two fools starving themselves, alone in their strongholds.

To think, that they could be so close as to share a body, so close that Thor can hear Loki speak from within his own mind… and yet there remain vast swaths of him still shrouded in a dense fog that Thor cannot hope to penetrate. 

Does Loki want him to push? Does he want Thor to go on the offensive, to take the lead? Or is this merely a game to him? Would he be affronted by the idea that their shared pleasure was to Thor far more than just a brief marriage of convenience? Would he want to do it again? What about when they no longer share a body?

There are just too many variables and Thor’s uncharacteristic indecision plagues him as he turns their situation over and over in his mind.

He keeps cycling back to Loki’s current mood, so oddly subdued these past several days— true, he never misses an opportunity to scold or criticize Thor, and he still occasionally chimes in with the friendly teasing and conspiratory remarks meant to embarrass Thor by spurring him to laughter. But he otherwise seems more morose with each passing day. Tired and drained, as if he sleeps ill in a skin not his own. There is some spark that has been dimmed and Thor needs to know why. 

Perhaps he frets most over the loss of his body— his sense of self, of autonomy. His much-valued privacy. For one such as Loki, this is surely a horrific punishment. Thor wonders if he is losing hope of finding a restorative. If he dreads the thought of being subject to the indignity of only existing within Thor, as an extension of him. Of his freedoms, his very life and existence being erased. 

Or possibly, Loki is resentful that his absence has gone seemingly unnoticed— that his simulacra are enough to fool the maids. That neither their family nor anyone else has been clamoring for his presence this week; which is, of course, perfectly in accordance with his stated wishes. Still, Thor knows this obedience would not possibly satisfy Loki’s absurd, endearing need to be constantly sought after so that _he_ might be the one to turn others down.

Yes, this is certainly another reasonable possibility for his evident sorrow.

Despite these pressing issues, however, Thor frets most of all over a fear most selfish— that Loki regrets what they’ve done. Perhaps Thor’s hopes were misplaced and Loki wants nothing to do with him. Perhaps he is shamed and disgusted by Thor’s response, or even by his own— he knows Loki is prone to self-loathing and cutting himself apart over the smallest perceived misstep. Perhaps he didn’t mean for it to go as far as it did and got carried away with pleasure, only to realize his mistake once his mind was clear. Perhaps he blames Thor for going along with his joke; for egging them on, for not stopping them as he should have. Just as it’s Thor’s fault they ended up like this to begin with. 

Worst of all, it’s possible Loki has discovered the true nature of Thor’s feelings for him and is staying as far away as he can, despite being bound to him. Norns, what if he feels that Thor is holding him captive?

Thor isn’t used to this level of over-thinking, but he imagines this must be what it’s like in Loki’s mind all the time. It’s frankly exhausting. And it makes Thor desperately wish for someone to consult on these matters, but even if he stole a private hour away from Loki, there is not a single soul he would trust to speak to. Not about this. 

He doesn’t remember having ever felt so alone. Loki was always his confidant for the things he knew his friends, his mentors and their parents would understand not.

_By the Tree, Thor. You’re thinking loud enough to rouse the dead._

Thor startles at Loki’s voice, realizes his eyes have yet again glazed over as he stares at the heavy book in his hands. How long has he been lost in thought? There’s a sudden spike of fear that Loki will _know_ the nature of his rumination, though Thor quickly stifles his reaction and calms his mind as best he can. 

“Sorry. Didn’t mean to drift off,” Thor replies, seizing on any distraction. He rolls his shoulders, stretching his arms up and behind his neck. “I’m not used to all this sitting. I’ve read more in the last few days than I have in the last few centuries. My hands yearn for hilt of my hammer. For something to _do_.”

As he hoped, Loki graciously takes the bait instead of questioning him further. _Ah. Finally, you admit to being an ignorant boor who only sees the value in smashing things he cannot understand?_

“Now you’re putting words in my mouth,” Thor counters— then, unbidden, remembers licking his own spend from his fingers, knowing Loki could taste him. A sudden flare of arousal low in his belly, another hint of a stir in his groin. Curse it all to Hel...

Of course, Loki doesn’t let it go without comment.

_That time again, hm?_

Thor hesitates before nodding. “I’ve been trying to put it off,” he says, carefully.

There is a pause, and then Loki’s agreeing, equally careful. _Yes, of course. Understandable, given the circumstances._ And was that a note of self-loathing?

Thor shakes his head. “No, I didn’t mean… I was just trying to spare you.”

 _How considerate,_ Loki says, an odd, unreadable tone in his voice.

“Unless in doing so, I am worsening your own predicament.” Thor treads lightly, not sure if he’s on the right path.

 _As much as it pains me to admit, I suppose your needs are somewhat priority, being as we are currently occupying your body. Do as you will._ Loki seems ready to drop the subject, but now Thor isn’t.

“Loki, you don’t… you aren’t subordinate to me. The situation is unusual, granted, but I wouldn’t have you feel less of a person just because you… er.”

 _No longer possess a person?_ Loki’s laugh is a bit high, edged with hysteria. _I think we can both agree I am little better than a parasite at this point._

“You’re still my brother,” Thor says, seriously, drumming his fingers on the table and staring absently at the wall in front of him. “And if you are indeed a parasite, then as your gracious host, I should be ensuring that you have all you need.”

Loki laughs again, bitterly. _So magnanimous of you._

“I mean it,” Thor says, rubbing a hand over his knee. “Parasite is the wrong word, anyway. You’re more of a… what’s the word? It’s symbiotic. You aren’t draining me. Well, except for the time where I nearly fainted, but I probably had it coming.”

Loki makes a dismissive hum, ignoring his weak attempt at humor.

“We’re both in this together, are we not?” Thor presses. “And the fault is mine, isn’t it? So whether you like it or not, I’m not leaving you to fend for yourself. Stop acting like you’re a burden. You’re not.” And then, recklessly, “and I’m not sorry this happened.”

He can feel a palpable wave of shock from within— rolling off Loki’s presence, mixing with his own. 

_Why would you say that? What is there to remotely like about this arrangement?_

Loki sounds less angered than Thor would have expected— he can sense his brother’s wary curiosity. 

The sudden certainty of what he’s about to do fills Thor with adrenaline. He takes a steadying inhale through his nose and takes the plunge. 

“I like feeling close to you. I couldn’t imagine doing this with anyone else. I wouldn’t _want_ to. But with you, it’s… good like this. Isn’t it?”

He senses Loki taking his own sharp breath— which makes no sense, really, because Thor’s lungs should be working for the both of them.

Thor feels a tremor run through him, fingers itching to be put to use. All this anticipation is seriously making him want to find something bludgeonable to take his nerves out on. Which is absurd. He doesn’t get nervous.

 _I can’t imagine this would’ve ever had cause to happen with anyone else, so the point is fairly moot._

And there it is, the deflection he’s been expecting. Thor smiles to himself. “So you don’t disagree.”

 _You don’t know what you’re saying, brother._ Loki’s voice is dismissive, flat, but Thor can feel something dancing on the edge of his senses. At first, he isn’t sure if his mind is playing tricks on him, but he feels… desire. Just a wisp of it. An echo of his own, reaching out toward him. 

His instinct is to let his hopes rise— to run toward it, grasp it firmly with both hands and demand the truth, but Thor knows he can’t. Not yet. Patience.

“I do,” he says, trying not to let his voice give him away as another swell of adrenaline stirs his blood. “And I mean it. Why wouldn’t I want to be near you?”

 _Near me! Oh, that’s rich. Trust you to speak sentimental drivel, with your eternal, misplaced optimism._ Loki scoffs, clearly riled. _This entire situation is a catastrophe through and through, you’re a fool to speak as if any good can possibly come of it._

“Something good already has,” Thor counters, subconsciously bringing a hand up to lay against his chest, fingers rubbing into the muscle where Loki last sank into him. “And it can happen again, if you want it.”

He’s pretty sure if he could see Loki’s face, it would be humorous to behold.

_Thor, honestly._

Thor just hums, sliding his hand over until he can tease one of his nipples through the soft fabric of his tunic, the only thing covering his chest. He feels trepidation and a sudden lashing of anger from Loki. Or is it fear?

_Stop._

“Stop what? Touching myself?” Thor asks, stroking with his nail until his nipple peaks under the fabric. “It’s my own body, after all. You said it was understandable, just a minute ago. And besides, I thought your needs were subordinate to mine? What was the word you used?” He feigns forgetfulness. “Ah, yes… parasite.”

_Enough. You’ve made your point._

But Thor has gotten better at reading Loki’s signals— there’s palpable fear, yes, but the faint echo of desire has now become a humming current of undeniable hunger emanating from his brother. Thor thrills to feel it, a bubble of elation rising in his chest. The hope that he’d barely dared nurture now swells hot within him. Still, Thor tries to calm his breath, his flurry of excitement, for he fears Loki will only redouble his efforts to ignore his own need if it is exposed too brazenly.

Fine, then. Thor can take him at his word. Beat him at his own game, see how he likes it. Drive him to a desperation equal to Thor’s own.

“It’s alright Loki, we don’t have to live as equals.” He almost smiles as he says it, knowing it would enrage Loki. “You’re right. I’ll just do as I please and heed you not. After all, you’ve taught me all your tricks— what do I need you for?” He trails his other hand down to the waistband of his breeches, teasing his fingers into the coarse hair below his navel, following the trail downward.

Loki is silent now, but Thor is undaunted by the anger he feels coming from him. He’s nearly certain it’s not directed at him— not solely. 

Thor shoves his hand into his breeches to wrap around his thickening cock, waking it further. “Your needs don’t matter, after all,” he continues, blithely. “Your autonomy, your pleasure. It means nothing to me. I’ll just pretend you’re not even there.”

 _It’s for the best,_ Loki finally manages to agree, and underneath the ire, Thor can hear the weakness in his voice. Does he mean for Thor to hear? Or is it slipping through despite his best attempts at self-control?

Thor can bear it no longer. He snaps the book closed with one hand, rising from the desk and stalking his way over to the bed, keeping his strokes slow and deliberate. He reclines on the furs and pillows, tugging his breeches down around his thighs then twitching his tunic aside to fully expose his cock to the warm air. After a moment’s deliberation, he reaches for the oil much earlier than he normally would. He can feel his brother’s presence in his chest, his throat, the pit of his stomach. Trembling in anger and yes, yes, in clear, unmistakable desire. 

Thor allows himself a thrill at being able to feel it, this proof of his brother’s feelings, burning his insides like a brand. It’s something he never in a thousand millennia would have expected, and to sense it welling up _within_ him, mingling with his own ravenous hunger, so unmistakable… How can Loki pretend it is anything but perfection?

Ah, just you wait, brother. Now I know. And I will have you yet.

 _I cannot believe you’re truly this depraved._ Loki seems to be unable to keep quiet, having lasted all of fifteen seconds.

Thor tries not to grin too obviously in response.

“It’s really too bad you won’t be able to enjoy this,” he remarks, teasing up his cock in the way Loki had showed him, rippling his fingers in time. “I came up with this technique myself, you know. But you probably wouldn’t appreciate it.”

He feels a stab of annoyance mixed with amusement this time, and again, that flare of arousal, deeper and lower. Thor grows harder in response, lets himself groan a little, remembering that Loki seemed to like it when he was vocal.

_You are an absolute fiend and I despise you._

Despite his harsh words, Loki seems to be losing his grasp on his rage, his reactions shifting in a more favorable direction. Not that Thor’s ever had too many compunctions about riling him up, but it feels like a little victory.

So Thor just laughs, unlacing the low collar of his tunic with one hand until he can rip it over his head and cast it aside— he runs his fingers over his skin, feels the rasp of his calloused thumb on his nipple without any fabric in the way. Thor might not be as luxuriant as Loki, but he’s been around the courtyard more than enough times to know what he likes, and this is one of those things. Time for little Loki to learn more about his body and its responses; he can’t wait to be able to return the favor.

Thor is pleased when his attentions quickly garner a surge of heat from both of them. A little prickle travels up his neck, and then Thor realizes with a start that there is an actual tendril of cool-warm quicksilver trailing over his shoulder, curling around the muscle. Squeezing.

Thor can barely breathe, hand stilling on his cock, just holding firm. He feels the tendril lengthening, gaining mass as it flows down over his chest to his unattended nipple and then—

“Ohhh…” Thor moans, eyes shutting and hips bucking, as that strange texture and pressure envelop the sensitive nub. It feels indescribably good, like fingers and lips and tongue all at once, all sex and slick, with just the right amount of velvety friction. 

He can’t help but jerk himself in response, to heighten the pleasure, then opens his eyes to see that the liquid has attached to his chest; shining, undulating tendrils anchoring to him like the grasping shoots of a fig vine. The greater part of its mass has coalesced into something like a hand— no, it’s _definitely_ a hand, teasing him now. Long and slender fingers. Graceful and dexterous. He’d recognize that hand anywhere.

 _Is this what you wanted? Is this why you’re buttering me up?_ He hears Loki’s low, rich voice almost as if it’s murmuring into his ear. _Let’s have it, then. Which shape shall I take for you? Who is it you desire, brother?_

Something that feels strangely like teeth closes around Thor’s nipple and he bucks and cries out, unbearably hot under his skin. He shakes his head and opens his mouth to speak, but Loki just laughs and cuts him off.

 _Ah yes, I can tell you’ve had much on your mind. Well, it won’t be my finest work but I will endeavor to assist you with your distraction from our predicament. It’s the least I can do._ The bitterness with which he shapes each word is a dagger in Thor’s heart.

Thor can only bite down on his lip as he feels another hand wrapping around his torso, coming around from beneath him. He is suddenly mesmerized by the marbled silvery-violet liquid, almost glowing against his own skin. “I’m not buttering you up,” he starts, but it’s the wrong angle.

 _Coward,_ Loki spits, interrupting him once more. His silvery hand digs into Thor’s hip, the half-formed forearm rippling and flowing in agitation. He stops all other movement and it makes Thor whine.

“No,” he protests, shaking his head even as he gasps. Loki’s hand swiftly finds his own on his cock and squeezes it, forcing Thor to grip himself tighter. It’s plain to see from his anger that Loki thinks himself being used, and Thor groans, this time in frustration. “No, Loki. That’s not at all—“

 _Why not?_ Loki roars. _Who is it? I’m dying of curiosity, brother. Whatever keeps your mind so constantly occupied? Tell me, is it Sif? Or perhaps Fandral? Who has you so desperately enraptured that you cannot go a day without subjecting me to your inane emotions?_

It’s jealousy that drives him, Thor realizes with a shock. Loki is _jealous_. He doesn’t trust that Thor’s desire is for him— and why should he? The realization fills him with a strange optimism. Enough so that he doesn’t fully consider his next words until they’re spilling from his lips.

“You,” he says, far too loud in the otherwise quiet room. “You gods-forsaken fool, it’s always been you.”

There is a pregnant pause. 

And then Loki laughs, a sharp and pained sound. _Well played,_ he growls, tweaking Thor’s nipple hard before sliding his hand up to Thor’s throat, squeezing. The other hand has taken over Thor’s cock, working him fast and hard, without mercy. How Thor loves it. Tears spring to the corners of his eyes. Oh gods, he wants. _Do you think I’m a complete imbecile?_

“Yes, I do,” Thor groans, rolling his hips up into Loki’s slicked, fluid grip— the sensation nearly overwhelming coupled with the pace he’s moving at. “But only because you won’t believe me. I swear to you, this isn’t a trick. Nobody’s laughing.” He gasps as Loki’s hand tightens under his jaw, threatening to cut off blood flow. “Let me prove it to you.”

 _Why should I believe you?_ Loki hisses.

Thor doesn’t hesitate. He thinks as hard as he can at Loki— all but shouts it at him as he lets out all the choked-back desire and longing, all his desperate hope and love surging to the forefront of his mind. Hoping that it will somehow reach across to Loki. His heart is pounding, his head swimming, his body prickling with tension and with sweat.

Loki quickly releases his grip on Thor’s throat, hands jerking back as if burned. 

_What is this,_ he demands, a growl in his voice that doesn’t quite cover how he’s trembling. 

“The truth,” Thor says, lightheaded from the blood rushing back to his head, feeling strangely light as air and incredibly aroused and no longer nervous. Which is maybe stupid of him, but it feels good to get all that off his chest, whatever else may come.

 _Lies,_ Loki accuses, but Thor reaches out to take the quicksilver hand that hovers in front of him, drawing it to his lips and pressing a kiss to its shimmering, smooth surface. 

“You’d know if I was lying,” he murmurs against that strange cool-warm skin. “You know I’m not.”

Loki holds his hand still, not reacting, frozen. Thor looks up to where he imagines his brother’s face would be, if Loki were corporeal in front of him. 

“Tell me, Loki. I know you can feel what I feel. I know you don’t want to believe me, but you should.” Again, he summons up all his fondest feelings, all his desires, his long-held wishes. Holds them up to the thin barrier inside that separates them. Coaxes Loki to him. 

_Can’t you see now, brother?_ He asks, mind to mind.

 _No… it shouldn’t be this way,_ Loki mutters, forlorn. _It wasn’t_ supposed _to go like this._

Thor feels a surge of helplessness and frustration from his brother.

“What wasn’t?” Thor all but whispers. He needs Loki to say it. Needs to hear it back.

 _The least you could have done was wait until I had my own body back before pouring out all your innermost feelings, you absolute cretin._ The frustration Thor had detected is now shot-through with a defeated hint of humor. Swift in pursuit is Loki’s unleashed desire, now surging at Thor so strongly that for a moment, it knocks him back and takes his breath away.

“I don’t care. Norns, I don’t fucking care,” Thor reassures his brother once he’s regained the ability to speak, pressing another kiss to the palm of the hand he still holds in his own. Strokes his thumb over the wrist of the other hand that’s been hovering uncertainty around his cock. “Maybe it wouldn’t have happened at all if it wasn’t for this.” He feels tears prick at his eyes, hot and sudden.

 _Sentimental fool._ But he can hear a reluctant grin in Loki’s voice and knows he’s getting somewhere. A wave of happiness crashes through Thor’s entire being as it really starts to sink in— that Loki truly wants him. That they can _have_ this, if they’re bold enough to reach out and take it.

“Love me like this now,” Thor speaks quietly, hoarse and choked. “And I will love you a hundred times over when you are back in your own limbs.”

A curl of dry amusement. “Only one hundred?”

And then the mercurial hand in Thor’s is slipping free to drift closer, shining softly as it cups his cheek and twines through his short cropped beard. Thor closes his eyes. Impossibly, it still smells like Loki— like cedar and citrus and leather. And then he feels the hand shifting, and suddenly there’s the velvety press of lips against his own, warm-cool. 

Instinctively, Thor means to bring his arms up to surround a body that isn’t there, but then he finds himself restrained. He doesn’t resist, letting his eyes stay closed as he kisses Loki back, just feeling the sweet pressure of their mouths, soft and exploratory. He can feel the tendrils emerging from all over his torso, front and back, and they’re thicker and longer now, caressing and slipping around him until Thor feels wrapped tight in their firm embrace, arms held to his sides.

He groans deep in his chest at the sensation, entirely too close to his guilty fantasy, and his cock jerks in Loki’s loose grip, which seems to have remembered what it was doing and quickly resumes stroking and caressing. Thor moans again, mouth falling open. Loki’s quicksilver tongue flows into his mouth, molding and slipping against his, neither liquid nor solid but something perfectly in between. Thor deepens the kiss, open-mouthed and desperate, and Loki matches his passion without missing a beat. It sets his entire body aflame, pangs of lust running straight to his groan, and he inhales deeply, helplessly, wanting even more and not knowing how to get it.

Loki forms a new hand to cup his jaw once more; yet another appears at the other side of his face. There is still a third hand around his cock, giving him those long, firm strokes he’s come to love. Thor feels Loki’s fourth and fifth hands parting his thighs and squeezing his flesh, fondling his balls.

Thor groans from the deepest nadir of his chest as he feels the brief tease of something firm and velvety slick at his entrance. It doesn’t feel like fingers. The tight ring of muscle twitches and quivers and Loki hums, pleased, into his mouth. He finally pulls back and it’s then that Thor blinks his eyes open and with a shock, realizes he’s staring at Loki’s entire face— all rendered in shifting violet and silver, shimmering with soft reflections. 

He is here, truly here, down to every last detail, yet so unreal that Thor can only gaze, amazed as more of Loki’s body seems to form— his hair, and then his neck and torso, rising from the silvery pool where he joins with Thor’s abdomen.

 _I can’t do my entire body yet,_ Loki says, mouth moving but voice still inside Thor’s head. _But I’ve been practicing._ There’s something on his face that looks almost nervous, as if he expects Thor will even now reject him.

Thor looks at him with unabashed need and relief. He hadn’t realized just how badly he needed to see Loki’s face, no matter the medium in which it was rendered. 

“Loki,” he says, unable to keep from smiling, then shivers as one of Loki’s thumbs digs into the meat of his thigh. “You look beautiful.”

Loki laughs, ducking his head slightly, and Thor wishes he could see him blush. _Don’t be an idiot. I’m a molten puddle of goo._

“I believe you’ve just described me as well,” Thor laughs, turning to press a kiss into one of the palms still at his cheek. “I’d say we’re evenly matched.”

Loki doesn’t laugh this time, just looking searchingly at him, eyes darting over his face. _Why?_ he asks.

Thor just smiles, softer, gentler. Letting his eyes run over Loki’s silvery violet face.

“I’ve asked myself that question time and time again, for centuries.” He doesn’t miss the way Loki’s eyes widen. “And the only thing I can conclude is that there was never any other way. I was always going to want you.”

For a moment, Loki’s expression is unreadable— him being somewhat reflective doesn’t make parsing his moods any easier— but then he lets out a slow exhale, though Thor feels no breath. 

_Sentimental fool,_ he says again. An undisguised endearment this time.

Thor is about to reply, but then he feels Loki’s hands at work on his cock again, a flurry of motion as Loki’s tendrils tug his breeches all the way off, then wrap around his hips, lifting them from the bed. Two fingers are pressed into Thor’s mouth and he bites down on them gently, sucking at them and marveling at their addicting taste, just like Loki’s tongue— faintly metallic, yet somehow sweeter, fleshier than he’d expected. 

_I want to take you,_ Loki says, suddenly, a hushed confession, and the words make Thor groan around the fingers in his mouth. He feels the hands at his thighs kneading, feels that slick press against his rim once more— picking up where they left off. His arms are still bound to him, the weight of his lower body completely supported by Loki’s mercurial form. 

Loki withdraws his fingers for a moment and Thor licks his lips, staring into the shifting depths of Loki’s eyes.

“Then have me,” he urges. “Take what is rightfully yours.”

Loki moans inside his mind, surging forward to kiss him again, this time in a messy, glorious spill of quicksilver that runs over Thor’s face, down his neck, before being reabsorbed. Through the haze of arousal and bliss, Thor feels the tendrils loosening one of his hands, guiding his arm down— Loki means to do the same as last time. Thor pulls his head free, shaking it.

“No. Only you.”

It’s hard to tell for sure, but he thinks Loki’s pupils dilate at that.

 _Are you sure?_ Loki asks, tendrils and hands seeming to touch him everywhere at once. _I don’t— you said you hadn’t had anyone else. And, gods, look at me Thor, I’m still…_

Thor can hear the need in his voice, battling with whatever doubt is holding him back. He presses another kiss to Loki’s soft palm. 

“Why do you think I waited all this time? Of course I’m sure.”

Loki’s eyes are wide now, so wide he looks like a skittish colt. 

“Give me all you’ve got,” Thor urges, straining up toward him. “Give me your cock or your hand or whatever other shape you like, I know you won’t hurt me.”

Loki’s hands are still stroking and kneading at him, but he bites his lip, looking down at the scene below— at his silvery hands on Thor’s skin, his viscous tendrils around Thor’s body. He looks unconvinced, so Thor adds, “We can do it again when you’ve got your body back, you nob. This isn’t your only chance. I just want you to have me like this, while we’re still joined.” He can’t help teasing. “What could be more special than our first time being while you’re literally living inside of me?” 

_I can think of a few, slightly less bizarre scenarios,_ Loki mumbles, meeting his eyes once more. _It’s strange enough even without the obvious added complication. I just don’t want…_ He doesn’t say the rest, but it’s clear what he means.

Thor smirks, tilting his head. “I won’t regret it. I couldn’t even if I tried. I want you as far inside me as you can get.” He lets his grin go wolfish. “Do you not recall how it felt last time? I came harder than I have in my entire life and I’m tempted to guess you felt similar. Now stop fretting and fuck me already.”

This finally gets the response he’s after— a wicked smirk darts across Loki’s face. 

_Well… if you insist, dear brother_ , he agrees, and that word makes Thor tingle all over. _And you’d better believe I will insist on a repeat when I have my own flesh returned to me._

“Enough talk,” Thor bucks his hips as much as he can, urging him onward. Loki dives in to swallow both his tongue and his gasps while a few of his tendrils push inside Thor, slipping easily past his rim, so slick and warm-cool and dizzyingly good. Thor’s eyes roll back as he feels Loki playing with the slit of his cock, swears there’s a tongue lapping at him and drawing the tip into a velvety smooth mouth, even as they’re still kissing.

“More,” Thor breathes into Loki’s slippery mouth, and hears a dark hint of laughter in reply. Suddenly, there are more tendrils attempting to breach him— or perhaps they’re just getting bigger— and Thor can feel them pressing thick at his entrance before forcing their way in, filling him so good, sliding against each other in and out so he’s never empty, just working him open little by little and stuffing him full.

 _So tight,_ Loki growls against his lips, and Thor cries out helplessly as his knees are drawn up further toward his chest even as his thighs are coaxed wider and held fast, exposing him to Loki’s attentions. Hands caress and tease his balls, supporting his ass as it’s eagerly plundered by Loki’s slick tendrils. They still play at his exposed nipples, running along his chest and hips and calves, squeezing and caressing. And all the while, that mouth continues to move enthusiastically on his cock, taking him in far enough that he can feel the throat spasm when Loki chokes around him; and yet the mouth that’s kissing him so deeply doesn’t hesitate for a moment. 

He can feel Loki everywhere, in and out, and it’s bar none the most erotic thing he’s ever experienced.

Thor can’t help a long whine as he feels Loki suck his tongue and grip his throat once more, something else reaching up to tug at his hair and pull his head back. The kiss breaks and he moans into the air as Loki’s lips trail down his neck, sucking and licking until he reaches where Thor’s shoulder begins— and he bites, harder than Thor would have thought possible in that form, and his cock throbs and jerks in the mouth that’s still swallowing him.

It’s so much, it’s beyond so much, and all the while, his own arousal is being magnified by Loki’s own, just as last time, and Thor lets out an undignified noise and doesn’t even care. “Loki, please. _Please_. I need you. Give me more...” Begging turns them on even further, the pleasure of it doubling and redoubling, and he hears Loki groan inside his head.

 _Mm… brother. I’m going to breed you so well._

The possessive, dominant tone in his rough voice sends a shiver through Thor— the thought of being truly subordinate is not something he’s used to turning him on, but this is a night for firsts. He bites down on his lip as he feels Loki’s tendrils retreat from his ass, leaving him feeling empty and aching, but then the blunt warm-cool head of a cock is nudging against his entrance, and he rolls his head from side to side as much as he can while his hair is still in Loki’s grip; eyes tightly shut, already in agony from wanting it so badly.

“Yes, brother… Give it to me. Please.”

 _So desperate,_ Loki teases, very nearly slipping the head in, then retreating. Thor all but growls in frustration, glaring at him, but that’s soon replaced by excitement when he senses his hips being tilted higher, with what appear to be solid thighs forming beneath him. Oil is being slicked around his entrance, coaxed inside of him with enough filthy noises to make a seasoned warrior blush. He can smell his own arousal.

Thor tugs his hair free of Loki’s grip and looks down, past where the remaining visible part of Loki’s upper body emerges from his chest.

He’s greeted by the sight of the silvery liquid coalescing separately into the lower half of Loki’s familiar, lean torso— a subtle curve to the hips and a gloriously thick cock. He sees the many fluid hands on him, sees the amorphous face engulfing his own cock with a tongue that leaves beads of silver behind before lapping them back up again. Thick tendrils binding his arms fast, even as they flow and reabsorb into each other, into his own skin. There’s just so much of him, everywhere. It’s all so fluid and sticky, so messy and good and terrifying, and it’s all Loki. 

Thor wants to be fucked by him so badly he can barely stand it. He feels more slick tendrils holding him open, spreading him, keeping him ready.

“ _Loki_ ,” he groans, gazing into his brother’s silver eyes in desperation, and Loki just laughs, licking his cheek, before the lower half of him finally presses his cock against Thor’s eager, twitching rim, then slips the head inside with a low grunt.

Only this time he doesn’t withdraw— even with the oil, even after being warmed up, it’s a slow, deliciously full push that drags along Thor’s insides and makes his eyes water as he gasps and trembles, until finally, finally, he can feel Loki is seated fully inside him.

“Is that really your cock?” He exhales, feeling his muscles flutter and spasm at the deliciously large intrusion. 

Loki laughs, breathlessly. _What do_ you _think?_

Thor moans, trying to rock his hips down into it, as if he could get more of Loki into him. “Gods, you’ve been holding out on me, we could have been doing this aeons ago.” He gasps, adding, “Don’t go easy on me, I want to feel this for weeks.”

_I wouldn’t dream of it._

He can almost feel Loki’s satisfied smirk, and then he begins to move, a slow undulating thrust, and Thor’s senses are under assault— the sheer girth of him, like nothing he’s had inside him before, just verging on pain but so so good, Thor wants more, wants it all. He almost chokes as he feels the tongue on his cock playing with his slit again, and then Loki’s setting a steady but deep rolling pace, sheathing himself inside Thor and biting his shimmering lip with perfect silver teeth.

 _Oh fuck,_ he says after a minute, eyes wide as they stare into Thor’s. _Oh gods, I can really feel you now. All of you._

And it’s true— Thor feels as though he’s both penetrating and being penetrated, can feel Loki’s arousal and pleasure as strongly as his own, can feel Loki both surrounding him and filling every inch of him until he can barely breathe, so close, as if they’ve truly merged into one being and the distinctions between them are ebbing and flowing with each breath, with each thrust of Loki’s quicksilver hips, growing faster now as they warm up and Thor’s body— their body?— accepts him, pulls him in, the sounds of Loki fucking him growing louder and messier.

Thor pants helplessly, little hurt noises escaping him. His mind is swimming in pleasure, in disbelief, in everything that is Loki. 

“Please, please, please,” he chants, tightening around Loki, and he feels Loki’s cock jump inside him, seeming to thicken even more. “Oh _GODS_ , Loki.”

Loki knows what he’s after, angles his hips until he’s found it— the spot that makes Thor jerk and try to choke back a shout. 

_Yes, Thor… let it out,_ Loki growls, his many hands and tendrils clutching and tweaking and smacking and tugging. _No one will see or hear you, shout as loud as you like. Let me hear you reduced to pitiful cries— Nghh. And screams. I would so_ love _to hear you scream, brother._

Thor makes something embarrassingly close to a whimper— how can he not, after that? It spurs Loki onward, driving harder into Thor’s prostate until Thor is crying out in agony, but now Loki’s wrapped the base of his cock tight, too tight, and it feels like he’s going to turn inside out in a shower of sparks and lightning.

 _I know you’re close,_ Loki teases, panting though he is, pulling back and slowing until he’s just barely brushing over the little pillowy mound inside. Thor makes a pained noise. Everything is throbbing. Loki suddenly smacks him across the chest, and again, just hard enough to make Thor cry out as his abused nipples smart and sting. Loki twists one of the stiff buds until Thor nearly howls, bucking his hips and trying to get more friction— somewhere, anywhere.

 _You want to come, but you look so good like this…_ Loki growls low, intimate, as he slides his hips forward a little harder, then harder still, quickly working Thor back up. _Hold on for me a little longer. I’ll take care of you, brother. You’re mine._ The last words are said in a snarl, a heavy wave of lust and adoration and sheer possession surging through their connection.

Thor all but sobs as Loki thrusts against his prostate, causing his limbs to shake and shudder. It’s so intense he can’t help but try to pull away, but Loki’s tendrils and hands and limbs hold him tight, so tight he can barely move, and Thor heaves a shaking breath, tears streaming down his cheeks. 

He can’t remember the last time he felt so free. So overwhelmed. So achingly full in every way. 

“Loki,” he moans wetly. “Oh Norns, Loki. I— oh fuck… fuck!”

Loki seems to take pity on him then; he covers Thor’s eyes with one tendril as another— thick, fat, twisting— nudges Thor’s lips open, surges slick against his tongue so Loki can fuck him here too, just as Thor’s cock is swallowed down once more by an unseen orifice, while the tendrils binding his arms twist and stroke and clench around him, Loki’s cock still fucking hard and sweet and unrelenting into Thor’s ass, lighting up both of their nerves until Thor swears they will combust— and oh, he can feel the surge of pleasure that means Loki’s about to come— the tendril in his mouth so heavy, heavy on his tongue— his saliva running down his face, mingling with his tears, and Thor moans deep and sucks hard, hard enough to hollow his cheeks just as he’s pushed over the edge by Loki’s orgasm, his whole body going rigid, and he’s being torn asunder, falling to pieces, a scream choked in his throat and his eyes opening into nothing, nothing but endless stars, something being pulled from so deep within that he nearly faints, his brother within him and surrounding him and holding him and breaking him with pleasure wreathed in white flames everything falling and writhing and crashing back into itself and oh Loki loki lo—

\+ + +

Thor claws his way back to consciousness. Slowly, groggily, and with much reluctance.

It’s a few long moments before he realizes something feels different. Sounds different. Thor blearily cracks open an eye, lashes sticking together with wetness, and then he realizes his arms are no longer bound, tingling with renewed blood flow. There is a weight on his chest, a cool hand over his mouth and soft hair tickling his neck. A slowly pulsing, softening cock still inside of him, warm spend slipping down the cleft of his ass. All is perfectly calm and serene, almost anticlimactic. As if this has always been the way of it. 

Thor takes a huge breath, then exhales long and slow against Loki’s palm before pressing a kiss to it. Realizes his chin is still wet and gingerly sets Loki’s hand aside to wipe at his messy beard with the back of his own. Loki barely stirs.

Thor tugs his brother closer, wraps his half-numb arms around him in a firm embrace, their skin sticking slightly as he tangles their legs together. He can’t help the hitch in his breath when Loki’s cock finally slips free of his body, and then he feels Loki’s lips nudge into a smile against his skin.

“How did you know?” Thor asks, mouth still lazy with the afterglow.

Loki nuzzles further into his chest. “I didn’t, really.” His voice is soft, sated, and he gives a happy sigh. “Just a hunch.”

“What kind of hunch…”

“Magic is a fickle beast, but it does have some...mmm, some general rules. To reverse a spell of dissolution—“

‘You have to create unity,” Thor realises, blinking into clarity. It seems so obvious now. 

“Mmm. Yes.” Loki’s voice is too slow and languid to sound surprised. “I figured the best way to unify my true body— to sift out the elements that didn’t belong— was to unite it in pleasure. Then I could use my seidr to isolate the non-reactive silver and help me shift back.” He pauses to yawn, and Thor feels his heart swell. His clever, astonishing brother...

“At any rate,” Loki continues, boneless on top of him. “I didn’t have the strength or ability to get myself to climax, as I was before. I needed your help. Your energy to pull from.” He gives a soft laugh. “Sex magic is a powerful thing. You made for a pretty good battery after all. Though I’m sorry if it felt a bit... unsettling, towards the end.”

Thor chuckles under his breath, stroking over Loki’s skin. “It wasn’t so bad. I think I enjoyed even that part.” Soft, velvet, firm. Both warm and cool. Not so very different after all. “And it wasn’t good enough to be within me when it happened, was it? Or you could have restored yourself after the first time we brought each other to completion...”

Loki’s hand runs idly over Thor’s side, making him shiver. “Very good. You’re learning. I had hoped the first time would be enough but it wasn’t. I knew I had to push it further. Make myself solid enough that I could be primarily outside you at the critical moment.” His lips twist in a wry grin that carries into his voice, his intonation gaining strength. “In hindsight, it might have been a bit messy were I to have reassembled myself inside your form.”

Thor grimaces, but he can appreciate Loki’s morbid humor now that it’s behind them. Something else dawns on him. “You’d been thinking of this for some time, then?” he asks, thinking of how things had unfolded between them with seemingly purposeful progression. “Not the first day, maybe, but… you probably suspected early on, didn’t you?”

His voice isn’t accusing but Loki sounds a little defensive when he replies. “Not right away, but once it occurred to me, I… may have made some preparations. I began to practice holding my shape each night while you were sleeping. It was the only real working theory I had, but still, I wasn’t certain it would be the _right_ thing to do.” He shrugs a shoulder, loose and seemingly unconcerned, despite his words. 

“What do you mean,” Thor asks, holding him just a little tighter. This explains a bit of Loki’s quietude the last few days, his lack of energy. But Thor senses there is more going on.

“Well… think about it,” Loki’s tone implies Thor is being deliberately obtuse. “It’s not as though I could’ve asked outright if you wanted to fuck me under normal circumstances— never mind when I was stuck as an amorphous, symbiotic entity relying on you for survival. I didn’t want you to be completely horrified. Or feel obligated.”

“Sure you could have asked,” Thor counters, not unkindly. “And even if it weren’t already my desire, I would have done it regardless, if it was the only way.” But he isn’t trying to chastise, for he would have feared much the same, in Loki’s position. It’s not as though he’d ever brought it up himself, after all. And Loki was ever less direct than he. 

“So you decided to feel me out first?”

“Felt you inside and out,” Loki confirms with a mischievous little smile, green eyes bright as he looks up at Thor. “I could tell you were harboring a great longing and affection for… something. Someone. I didn’t dare presume it might be for _me._ ” He pauses, as if marveling at his own words. “I knew you wouldn’t dare lay with another while we were joined. I hoped that you might be desperate enough for release that what I had to offer might seem a suitable substitute.” 

His eyes dart away from Thor’s face, lingering somewhere around his shoulder. “It wasn’t until the night at the river that I started to hope you might be amenable,” he confesses, quieter. “You seemed more comfortable with my form, then. Curious, even. The next morning, I decided to test you. To see what you were willing to do in my presence. You let me go so much further than I’d dreamed.” His glance darts back to Thor’s, a little color high in his cheeks, and Thor feels an answering flush rise to his, despite his better intentions. 

“From there,” Loki murmurs, staring at Thor’s lips, “I thought I’d worked out the rest of the plan. It was simple, really. I would goad you once more into taking your pleasure, protest and make you think it was all your clever idea, and then humbly offer my assistance, same as the first time.” He ignores Thor’s snort of indignation. “Don’t lie, you absolutely thought I was objecting in earnest the other day.”

“Only at first,” Thor gives a soft whuff, though he’s not truly offended. “How absurd of me to begin with the assumption my little brother _wasn’t_ trying to manipulate me into sex. And yes— I knew it was sex the first time, Loki. How could I think anything else?”

Loki shrugs. “I presumed that it would dawn on you at some point. I would have moved to the next phase of my plan the following day, before you could have too much time to dwell on it, only I hesitated. Told myself it would be more effective to wait, let you become desperate once more. For I assumed then it was only desperation driving you. When I felt your longing today, I couldn’t ignore the opportunity.”

“What was your original plan?” Thor wants to know, holding him closer, letting his voice drift lower, rumble from his chest into Loki’s. “To seduce me a second time? How did you imagine it?”

“I thought after you were aroused, I would propose allowing you to… to take me,” Loki’s voice hitches a little. “It seemed the safest way, more likely for you to agree. I would take whichever shape you most desired, to make it easier. If it was not enough to help me regain my form, you would not know to be disappointed. If it _did_ work, I presumed that would be the end of it. Either way, we would surely regard the whole thing as an embarrassment and never speak of it again.” He wets his lips, looking at Thor again with something hesitant and longing on his brow, in the tilt of his mouth. 

“I never thought to complicate it further than that. I didn’t realize you would _want_ it. And I didn’t expect to…erm.”

“Get jealous of yourself?” Thor offers, helpfully. “And then throw a fit?” Now it was making a bit more sense, why Loki had become so angered earlier, despite Thor unwittingly walking right into his machinations. His brother did so hate to get what he wanted.

Loki laughs, a bit chastised. “Perhaps I did get a bit carried away.” He traces a finger over Thor’s pectoral. “I didn’t think it would affect me so, but once I had you right where I wanted you, it suddenly seemed so— so unfair, that I not be in my true form. That as far as _I_ knew, it should all mean nothing to you— just an act of convenience or else desperation. Whereas for me…” Loki huffs a little, shaking his head and pursing his lips. 

“Even if I was all but certain the act would return my body to me, I didn’t know if I could still go through with it. Actually sleeping with you. To see what I was truly missing and to know that, if all went well, I would never have you again. It seemed either way I might be burdened with an unbearable torment.” 

He meets Thor’s eyes again, his humor having clearly returned. 

“Naturally, I decided the only sensible option was to yell at you— which turned out to be the right answer, so I feel rather justified in hindsight.”

Thor just laughs, shaking his head at his brother’s innate ability to overcomplicate things.

“Trust you to find a way to blame it all on me,” he teases, sitting up a bit against the pillows. Loki shifts in response, rising and straddling Thor’s waist. He makes a bit of a face as he does so, followed by a small hand gesture. Thor feels the sweat and stickiness of their coupling vanish, and though he somewhat misses the reminder of Loki having fucked him so thoroughly, he has to admit that it’s nice to not be sitting in a puddle of wet furs and tangled sheets.

Now that he can properly see more of Loki, Thor finds himself compelled to rest his hands upon the pale thighs that hug his torso, staring up at his beautifully disheveled brother and drinking in every last inch. His bright eyes and the lingering boyish curve of his cheek. His dark hair in messy waves framing a sharp, clever jaw. His long, delicate neck; his finely sculpted arms and clever hands; the sharp geometry of his collarbone.

Thor lets his gaze drift down linger on Loki’s limber torso, powerful and lean with muscle, tapering from broad shoulders to a slim waist, all rendered with just the right amount of appealing softness to make him weak at the sight. His eyes are drawn to the dusky peaks of his nipples and the thick rope of his cock, resting in its halo of dark curls. The power coiled in the thighs under Thor’s hands, reminding Thor of how loose he still feels, how it felt for Loki to split him open.

Could this man really be his? His glorious, frustrating, utterly ravishable little brother? Did Thor dare try to keep him for himself?

Words escape him for a long moment. Loki stares right back; eyes hopeful, Thor thinks. That hope, more than anything, is what spurs him onward.

“What you said earlier,” He clears his throat, breaking the silence. “When we were joined… you called me _yours_. I felt what you felt.” The question hangs in the air. Thor doesn’t normally go for subtlety but he wants Loki to meet him halfway.

Loki’s face flushes, just the barest tinge of pink over his cheeks and ears, but he doesn’t avert his gaze this time. “I meant every word,” he says, so uncharacteristically vulnerable that it makes Thor’s heart ache. “At first, I meant only to say enough to be sure of your willingness. But I am far too selfish to remain noble for long.” He hesitates, as if he fears he’s said too much. As if he still can’t quite believe that Thor might return the sentiment. “Although if that’s not what you desire, it doesn’t have to—“

Thor sits up and reaches out to cup his jaw, running a thumb over his lip to distract him from that line of thought. 

“Don’t you dare question for a single moment my desire,” Thor chides, gently. “I wasn’t exaggerating — I have wanted you for centuries, Loki. And each one has felt longer and lonelier than the last.”

Loki inhales, with feeling, and it brings a soft smile to Thor’s lips.

“I would have you and no other,” he continues, “for as long as you feel the same. And I would gladly take you and be taken by you in whichever form you choose. You are the shape I most desire, brother.” His eyes take in Loki’s face, the perfection of his hand against Loki’s jaw, how it fits like it was meant to be there. “And I would never have you make it easy on me. We were not meant for easy.”

After a moment, Loki’s mouth curls into a gentle grin under Thor’s thumb. “Is that so?” He wiggles his hips just a little against Thor’s. “Don’t be surprised if I decide to put those claims to the test.”

Thor strokes his cheek and Loki leans into his touch, closing his eyes for a brief moment. Have his lashes always been that long? 

They’re caught staring into each other again, not daring to speak. Not needing to. Eventually there’s a little tug at the corner of Thor’s mouth, or maybe it’s Loki who starts it, but they end up sharing a quiet laugh of relief as much as disbelief. Thor relaxes back against the bed, pulling Loki down with him, wrapping his arms around him. Loki softens against Thor’s chest, nuzzling in under his chin, and it occurs to Thor how exhausted he must be from his ordeal.

Thor presses a kiss to the top of his brother’s head, lays back and stares at the ceiling of his rooms, trying to process. Despite his utter joy at seeing Loki whole and hale once more, the shock and relief of finally having him in his arms the way he’s always dreamt, he can’t help but feel just a little pang of loss. A bizarre, selfish regret that their strange union had come to an end so that this new beginning might emerge.

 _It’s too bad,_ he thinks at Loki, stupidly. Wistfully. _In some ways, I was just beginning to—_

“Get used to it?” Loki interjects, turning his head up toward Thor with a grin.

Thor inhales sharply, seeing the flash of liquid silver clouding Loki’s eyes before they turn back to their usual vivid green. 

“Don’t worry,” Loki winks, sits up just enough so Thor can see him clearly as he holds up a hand. “It didn’t escape me how much you seemed to like them…” Thor watches in awe as his fingers seem to shimmer and undulate ever so briefly. Silvery lilac tendrils twine and bloom against his palm before settling back down beneath his skin.

Thor looks at Loki in disbelief and receives a secretive smile in response.

 _What, you didn’t think I’d give it up completely, did you? After all the fun we had? With all the experiments I could be doing?_ Loki tilts his head in perfectly condescending amusement, his voice clear and warm in Thor’s mind. _Do you know me at all, brother?_

Thor huffs out a weak laugh, covering his eyes with a hand, then quickly giving into full on body-shaking laughter, tears pricking at his eyes again as he’s overwhelmed with absurd joy. Loki just snickers at him, then waits patiently as Thor gets himself back under control.

He looks up at his brother, filled with more awe than he knows what to do with. He was wrong to fret even for a moment that they’d lost anything— for the truth is that somehow, impossibly, they’ve gained everything.

‘You…” Thor says, with feeling. 

“Me,” Loki agrees.

Thor gives into impulse and rolls them, flipping Loki onto his back so he can lean down and kiss him with two flesh-and-blood mouths for the first time, drinking in his taste and the feel of his lips, cool to the touch. Savoring the slick of his tongue and the warm smell of sex lingering about him. Pressing between Loki’s legs with the promise of what’s to come. 

When he finally pulls back, Loki is gazing up at him with a soft smile, lips swollen from their evening of kisses. He stares for a moment before reaching up to tuck a wayward strand of Thor’s hair behind his ear. He looks beautiful— more at ease than he has in years. Thor resolves that he will do whatever it takes to keep that look on his brother’s face.

 _I love you more than anyone has ever loved anything,_ Thor thinks, earnestly. _I will love you until the heat death of the universe. And then I will make a new one just for us so that I never have to stop._

He pauses, then asks, “Do you understand me, brother?”

From the look on Loki’s face, he’s heard every word.

**Notes for the Chapter:**

> Oh huh, what’s this epilogue doing here...?
> 
> Hit me on my beeper anytime (aka @seidrade on tumblr.)  
> xx


	4. Epilogue

**Notes for the Chapter:**

> A last, huge thank you to my wonderful beta ravenbringslight — go read her fic and follow her on tumblr, she’s amazing (my links aren’t working, sorry.) Again, I ransacked this after she saw it, so all mistakes are wholeheartedly mine.
> 
> And fwiw— so much appreciation towards you all for coming on this strange ride with me! Thank you for such a warm reception to my first posting on AO3! It’s really made my day reading your comments so thank you, thank you, thank you.
> 
> And I’ve got to admit, I’ve become pretty fond of this bizarre little verse. There were so many things that didn’t quite fit into this story— this wasn’t even originally going to have an epilogue, but then I couldn’t get this scene out of my head, and that’s what made me realize I wasn’t quite done with the symbiotic brotherhood. So... y’know. There will very likely be more coming. In for a penny...

Thor flies high above the battlefield, Mjolnir firm in his grip, taking in his enemies’ positions as he plummets back to the ground. 

He slams her down hard on the earth, lightning flashing and thunder rolling, the shockwave knocking all combatants in a twenty-meter radius off their feet. Arrows fly at him, but shimmering silver violet tendrils shoot out from his body and catch them, engulfing them in the blink of an eye then sending them back to their owners, business-end first, trailing plumes of green seidr.

Thor pivots and strikes, blow after blow, and any that would dare to lay a hand or weapon at his back quickly find they’re run through with great silvery tentacles, or else plucked up and whipped into the tree line so fast the air cracks around them. Thor laughs at the chaos of it, at the bloodlust racing through their veins, and he hears Loki gleefully spit colorful insults at their foes, cursing them up and down. He breaks free from Thor in a shimmer of green and gold to spin and whirl with his knives, felling everything in his path, then slips back into Thor to block more incoming arrows with a large silver shield, protecting their flank. 

Even when they’re not in one body, their sense of the other is heightened, perceiving each others’ position perfectly. They’ve devised a shorthand language of thoughts which flows more rapidfire than words; just a brush of images and impressions. They fight in near-perfect harmony, never once stepping in each others’ way, and the thrill of it is almost as good as fucking. Almost.

And then, there, at the edge of the clearing, they both clock it at the same time. The creature is massive, fiery, and doesn’t look best pleased. 

_Muspelwyrm_ , Loki breathes, eager. _They brought their champion to test us._ Before Thor even has to ask, there’s the familiar sensation of Loki’s quicksilver flowing over his skin, forming a protective armor. It covers even his face, but he can see and breathe just fine. He feels Loki’s anticipation thrumming through them and answers in kind, adjusting his grip on Mjolnir. 

They grin.

The remaining brawlers look between the two opponents, then quickly hightail it out of the way. Nobody wants to get close to the massive fiery monstrosity, nor the giant silver man holding a bloody warhammer, lightning in his eyes and massive, curling goat horns jutting sharp and wicked from his head.

 _Ready when you are, my love,_ one of them says.

The Muspelwyrm screeches terribly and lowers its head to charge, and then they’re flying to meet their foe. 

The battle is quick but fierce— it takes all of their cunning and strength to avoid the acid the beast spits at them, to keep from being pinned in its flaming coils, to find the weaknesses in its near-impenetrable hide. Loki swings Mjolnir hard into its jaw, dislocating it, and Thor lets out a bloodcurdling roar as he unleashes a wave of seidr into its gaping maw, disintegrating its teeth and snapping its head back with a sickening crunch.

They leap clear as the beast falls, but still it thrashes, and so they deal it a mercy stroke, channeling lightning down a long spike of silver that they drive into its broken skull.

And then it is done. They step back, surveying the battlefield, but the remaining enemies have scattered— their lines broken, their leaders vanquished. The Vanir troops will be able to pick them off in the forest or else capture them— the princes’ job is done for now.

The quicksilver flows back over Thor’s skin, receding inside of him, and he watches the giant horns disappear from the shadow they cast on the scorched earth. He turns to see Loki has emerged at his side, green eyes wild and hair only a little mussed. He doesn’t even look as if he broke a sweat, the vain sod, but Thor knows he’ll be able to taste the salt on his skin.

Loki nods at him, then casts his eyes about the field once more, to ensure they are yet alone, before stepping in closer.

Thor grins fondly, pulling him in for a messy kiss, and Loki fists the hair at the back of his head, biting at his lip; battle-hungry in a way he never was before they began to fight together like this. His beautiful, fierce little brother. 

_Let’s go get cleaned up,_ Thor suggests, squeezing Loki’s ass as he presses their hips together.

The look Loki gives him then is one of Thor’s favorites— a playful, utterly lascivious expression which will surely one day be declared illegal in at least three realms and several star systems, based on what inevitably seems to follow it.

 _I love it when you talk dirty,_ he teases, making Thor groan on two entirely different levels.

“Cease with your terrible jokes or I’ll have you right here and right now on this filthy, stinking battlefield,” he says aloud, because he wants Loki to hear every little nuance of his voice. How eager he is for him.

Loki just grins, a sharp and wicked thing, and Thor sees his brother’s eyes cloud over with fluid silver. A frisson of delight runs down his spine and Loki gives him another of Thor’s favorite, penetrating looks; knowing entirely too well what he wants.

“You should be so lucky to receive me.” And, because his brother can never resist a taunt, “Let’s see you on your knees, your _Majesty_.”

Thor is unable to resist grinning back even as his arousal surges and he sinks to his knees, safe in the knowledge that Loki will hide them from sight if needs must. 

“On that note,” he says, taking Loki firmly by the hips. “Remind me to tell you later about an idea I had. I think you’re going to like it…”

**Notes for the Chapter:**

> Some final notes: The ‘tropic’ of the title refers to being in the state of turning/transforming. And speaking of trickster symbolism; while Loki’s symbiote form might not be literally made of quicksilver (for many, hopefully obvious reasons), it’s such a perfect symbol for him that I couldn’t resist Thor using it as something of a kenning. Actual mercury does indeed conduct electricity quite nicely without retaining excess heat and can kill you without breaking a sweat. That’s my boy.
> 
> Feel free to find me on tumblr at @seidrade!  
> xx  
> 


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